CNO Report # 246
Release Date 03 AUG 2017
Draft Report Compiled by
In this Issue:
1. More evidence shows natural plant compound may reduce mental effects of aging
2. Lutein and zeaxanthin isomers benefits during high screen exposure
3. Why strength depends on more than muscle
4. Drinking coffee reduces risk of death from all causes, study finds
5. Nanoparticles loaded with component of common spice kill cancer cells
6. UAlberta and McGill scientists uncover a hidden calcium cholesterol connection
7. Vitamin E-deficient embryos are cognitively impaired even after diet improves
8. Green tea ingredient may ameliorate memory impairment, brain insulin resistance, and obesity
9. An end to cavities for people with sensitive teeth?
Public Release: 10-Jul-2017
LA JOLLA–(July 10, 2017) Salk scientists have found further evidence that a natural compound in strawberries reduces cognitive deficits and inflammation associated with aging in mice. The work, which appeared in the Journals of Gerontology Series A in June 2017, builds on the team’s previous research into the antioxidant fisetin, finding it could help treat age-related mental decline and conditions like Alzheimer’s or stroke.
“Companies have put fisetin into various health products but there hasn’t been enough serious testing of the compound,” says Pamela Maher, a senior staff scientist in Salk’s Cellular Neurobiology Laboratory and senior author of the paper. “Based on our ongoing work, we think fisetin might be helpful as a preventative for many age-associated neurodegenerative diseases, not just Alzheimer’s, and we’d like to encourage more rigorous study of it.”
Maher, who works in the lab of David Schubert, the head of Salk’s Cellular Neurobiology Lab, has been studying fisetin for over a decade. Previous research by the lab found that fisetin reduced memory loss related to Alzheimer’s in mice genetically modified to develop the disease. But that study focused on genetic (familial) AD, which accounts for only 1 to 3 percent of cases. By far the bigger risk factor for developing what is termed sporadic AD, as well as other neurodegenerative disorders, is simply age. For the current inquiry, Maher turned to a strain of laboratory mice that age prematurely to better study sporadic AD. By 10 months of age, these mice typically show signs of physical and cognitive decline not seen in normal mice until two years of age.
The Salk team fed the 3-month-old prematurely aging mice a daily dose of fisetin with their food for 7 months. Another group of the prematurely aging mice was fed the same food without fisetin. During the study period, mice took various activity and memory tests. The team also examined levels of specific proteins in the mice related to brain function, responses to stress and inflammation.
“At 10 months, the differences between these two groups were striking,” says Maher. Mice not treated with fisetin had difficulties with all the cognitive tests as well as elevated markers of stress and inflammation. Brain cells called astrocytes and microglia, which are normally anti-inflammatory, were now driving rampant inflammation. Mice treated with fisetin, on the other hand, were not noticeably different in behavior, cognitive ability or inflammatory markers at 10 months than a group of untreated 3-month-old mice with the same condition. Additionally, the team found no evidence of acute toxicity in the fisetin-treated mice, even at high doses of the compound.
“Mice are not people, of course,” says Maher, “But there are enough similarities that we think fisetin warrants a closer look, not only for potentially treating sporadic AD but also for reducing some of the cognitive effects associated with aging, generally.”
Next, Maher hopes to partner with another group or company in order to conduct clinical trials of fisetin with human subjects.
Public Release: 10-Jul-2017
OmniActive Health Technologies
Morristown, N.J., July 10, 2017 – An exciting new peer reviewed publication based on ongoing research on macular carotenoids from the University of Georgia demonstrates that supplementation with lutein and zeaxanthin isomers can protect against a growing issue among the general population — the undesirable effects of prolonged exposure to high-energy blue light emitted from digital screens of computers, tablets and smartphones. Lutein and zeaxanthin isomers — known as the macular carotenoids — are natural filters of high-energy blue light. High-energy blue light reaches deep into the eye and can harm the macula — the region of the eye responsible for highest visual acuity- by promoting the production of free radicals. Short-term effects can cause eye fatigue while long-term exposure can lead to a progressive loss of visual function.
The B.L.U.E. study (an acronym for Blue Light User Exposure) was the subject of a recent paper, “Effects of macular carotenoid supplementation on visual performance, sleep quality, and adverse physical symptoms in those with high screen time exposure,” published in Foods 2017 (Stringham, et al.). This is the first study to examine the impact of macular carotenoids supplementation to protect visual health and performance, improve sleep quality and reduce eye strain and fatigue during prolonged exposure to blue light emitting digital screens.
“The effects of blue light on vision isn’t new. However, 10 years ago we saw a surge in near field technology holding or using devices within arm’s length, resulting in increased complaints around high screen use — neck pain, eye strain and fatigue, headaches.” Stated Dr. James Stringham, the lead author of the paper. “This has led to an opportunity with supplementation — a simple mode of therapy with specific nutrients that have a wealth of benefits as they deposit in the eye. After six months of supplementation we saw significant reduction around 30% in these symptoms and significant improvement in measures of visual performance and protection.”
The B.L.U.E. study was a 6-month randomized, double-blind, placebo-controlled supplementation trial with 48 healthy, young adults with screen time exposure of at least 6 hours daily. Subjects were evaluated at baseline, 3-months and 6-months for MPOD (Macular Pigment Optical Density) and markers of visual performance including contrast sensitivity, photostress recovery and disability glare. Sleep quality, which is affected by blue light exposure, and physical indicators of excessive screen use were also measured. The results show that supplementing with Lutemax 2020 significantly improved macular pigment optical density, visual performance and indicators of excessive screen use, including eye strain and fatigue and headache frequency. Sleep quality also improved significantly.
“At home, work and school your eyes are focused on digital devices for long periods of time. In many cases we spend more time staring into digital screens than sleeping.” said Abhijit Bhattacharya, President, OmniActive Health Technologies Ltd. “Even Children, whose eyes are more susceptible to the harmful effects of blue light, spend almost half their day staring into screens. This study is groundbreaking – the first of its kind. And builds on an impressive body of evidence on Lutemax 2020 and its impact on vision and brain health. The BLUE study has huge implications because it addresses the growing concern of prolonged ‘screen time’ that is happening across all age groups and offers a simple solution to protect the eyes in this digital age.”
Public Release: 10-Jul-2017
Neural adaptations could account for differing strength gains despite similar muscle mass
University of Nebraska-Lincoln
A recent study from the University of Nebraska-Lincoln has given new meaning to the concept of brain power by suggesting that physical strength might stem as much from exercising the nervous system as the muscles it controls.
Over the past few years, researchers have found evidence that lifting more repetitions of lighter weight can build muscle mass just as well as fewer reps of heavier weight. Even so, those who train with heavier weight still see greater gains in strength than those who lift lighter loads.
But if strength differs even when muscle mass does not, what explains the disparity?
Nathaniel Jenkins and his colleagues may have uncovered some answers by measuring how the brain and motor neurons – cells that send electrical signals to muscle – adapt to high- vs. low-load weight training. Their study suggests that high-load training better conditions the nervous system to transmit electrical signals from the brain to muscles, increasing the force those muscles can produce to a greater extent than does low-load training.
Muscles contract when they receive electrical signals that originate in the brain’s neuron-rich motor cortex. Those signals descend from the cortex to the spinal tract, speeding through the spine while jumping to other motor neurons that then excite muscle fibers.
Jenkins found evidence that the nervous system activates more of those motor neurons – or excites them more frequently – when subjected to high-load training. That increased excitation could account for the greater strength gains despite comparable growth in muscle mass.
“If you’re trying to increase strength – whether you’re Joe Shmoe, a weekend warrior, a gym rat or an athlete – training with high loads is going to result in greater strength adaptations,” said Jenkins, an assistant professor of exercise physiology at Oklahoma State University who conducted the research for his dissertation at Nebraska.
The dissertation randomly assigned 26 men to train for six weeks on a leg-extension machine loaded with either 80 or 30 percent of the maximum weight they could lift. Three times per week, the participants lifted until they could not complete another repetition. Jenkins was able to replicate the findings of several previous studies, seeing similar growth in muscle between the two groups but a larger strength increase – roughly 10 pounds’ worth – in the high-load group.
But the researchers also supplied an electric current to the nerve that stimulates the quadriceps muscles used in leg extensions. Even at full effort, most people do not generate 100 percent of the force their muscles can physiologically produce, Jenkins said. By comparing the force of a participant’s “hardest” unassisted kick with the maximum force they can generate when aided by electric current, scientists can determine how much of that capacity a person has reached – a measure known as voluntary activation.
When adjusting for baseline scores, the researchers found that the voluntary activation of the low-load group increased from 90.07 to 90.22 percent – 0.15 percent – over a three-week span. The high-load group saw their voluntary activation jump from 90.94 to 93.29 percent, a rise of 2.35 percent.
“During a maximal contraction, it would be advantageous if we are activating – or more fully activating – more motor units,” Jenkins said. “The result of that should be greater voluntary force production – an increase in strength. That’s consistent with what we’re seeing.”
Jenkins also tested his hypothesis another way, asking participants from both groups to kick out at 10-percent intervals of their baseline strength – from 10 percent all the way up to 100 percent – after three and six weeks. If high-load training does improve muscle efficiency better than low-load training, he reasoned, then high-load lifters should also use a smaller proportion of their strength – that is, exhibit lower voluntary activation – when lifting the same relative weight.
That’s what the data generally showed. Voluntary activation in the low-load group did decrease slightly, from an average of about 56 percent at baseline to 54.71 percent after six weeks. But it decreased more in the high-load group, dropping from about 57 to 49.43 percent.
“If we see a decrease in voluntary activation at these sub-maximal force levels, that suggests that these guys are more efficient,” Jenkins said. “They are able to produce the same force, but they activate fewer motor units to do it.”
Placing electrodes on the participants to record the electrical signatures of their quadriceps reinforced those results. High-load training led to a substantially larger drop in electrical activity after six weeks, the study reported, and that activity was lower across most levels of exertion.
“From a practical standpoint, that should make the activities of daily living easier,” Jenkins said. “If I’m lifting sub-maximal loads, I should be able to do more repetitions with fewer motor units active, so maybe I fatigue a little bit slower.”
Jenkins maintained that low-load training remains a viable option for those looking to simply build mass or avoid putting extreme stress on joints, a priority for older adults and people rehabbing from injury. Still, he said, the new study lends even greater credence to the notion that when it comes to building strength – especially amid a busy schedule – heavier is better.
“I don’t think anybody would argue (with the idea) that high-load training is more efficient,” Jenkins said. “It’s more time-efficient. We’re seeing greater strength adaptations. And now we’re seeing greater neural adaptations.”
Jenkins detailed his findings in the journal Frontiers in Physiology. He authored the paper with former doctoral adviser Joel Cramer, associate professor of nutrition and health sciences; Terry Housh, professor of nutrition and health sciences; Nebraska doctoral students Amelia Miramonti, Ethan Hill, Cory Smith; and doctoral graduate Kristen Cochrane-Snyman, now at California State Polytechnic University.
Public Release: 10-Jul-2017
Imperial College London
People who drink around three cups of coffee a day may live longer than non-coffee drinkers, a landmark study has found.
The findings come from the largest study of its kind, in which scientists analysed data from more than half a million people across 10 European countries, including the UK, to explore the effect of coffee consumption on risk of mortality.
Researchers from the International Agency for Research on Cancer (IARC) and Imperial College London found that higher levels of coffee consumption were associated with a reduced risk of death from all causes, particularly from circulatory diseases and diseases related to the digestive tract.
Coffee is one of the world’s most commonly consumed beverages, with an estimated 2.25 billion cups drank around the world each day. It contains a number of compounds which can interact with the body, including caffeine, diterpenes and antioxidants, and the ratios of these compounds can be affected by the variety of methods used to prepare coffee.
Previous studies looking for a link between coffee consumption and health outcomes have revealed conflicting results, however, large studies in both the US and Japan have since revealed a potential beneficial effect of drinking coffee on risk of death from all causes.
In the latest study, published in the journal Annals of Internal Medicine, researchers have carried out the largest analysis of the effects of coffee-drinking in a European population – where coffee consumption and preparation methods vary, from an espresso in Italy, to a cappuccino in the UK – finding a similar association between consumption and mortality.
“We found that higher coffee consumption was associated with a lower risk of death from any cause, and specifically for circulatory diseases, and digestive diseases,” said lead author Dr Marc Gunter of the IARC and formerly at Imperial’s School of Public Health. “Importantly, these results were similar across all of the 10 European countries, with variable coffee drinking habits and customs. Our study also offers important insights into the possible mechanisms for the beneficial health effects of coffee.”
Using data from the EPIC study (European Prospective Investigation into Cancer and Nutrition), the group analysed data from 521,330 people from over the age of 35 from 10 EU countries, including the UK, France, Denmark and Italy. People’s diets were assessed using questionnaires and interviews, with the highest level of coffee consumption (by volume) reported in Denmark (900 mL per day) and lowest in Italy (approximately 92 mL per day). Those who drank more coffee were also more likely to be younger, to be smokers, drinkers, eat more meat and less fruit and veg.
After 16 years of follow up, almost 42,000 people in the study had died from a range of conditions including cancer, circulatory diseases, heart failure and stroke.
Following careful statistical adjustments for lifestyle factors such as diet and smoking, the researchers found that the group with the highest consumption of coffee had a lower risk for all-causes of death, compared to those who did not drink coffee. They found that decaffeinated coffee had a similar effect. However, consumption of caffeinated and decaffeinated coffee is not simple to separate, as they could not exclude that decaffeinated coffee drinkers may have been consuming caffeinated coffee as well in different periods of their life.
In a subset of 14,000 people, they also analysed metabolic biomarkers, and found that coffee drinkers may have healthier livers overall and better glucose control than non-coffee drinkers.
“We found that drinking more coffee was associated with a more favourable liver function profile and immune response,” explained Dr Gunter. “This, along with the consistency of the results with other studies in the U.S. and Japan gives us greater confidence that coffee may have beneficial health effects.”
According to the group, more research is needed to find out which of the compounds in coffee may be giving a protective effect or potentially benefiting health. Other avenues of research to explore could include intervention studies, looking at the effect of coffee drinking on health outcomes.
Professor Elio Riboli, head of the School of Public Health at Imperial, who established the EPIC study, said: “These findings add to a growing body of evidence which indicates that drinking coffee not only is safe, but it may actually have a protective health effect for people. While further research is needed, we can be confident that the results from a large European study confirm previous findings seen around the world.”
Dr Gunter added: “Due to the limitations of observational research, we are not at the stage of recommending people to drink more or less coffee. That said, our results suggest that moderate coffee drinking – up to around three cups per day – is not detrimental to your health, and that incorporating coffee into your diet could have health benefits.”
Public Release: 25-Jul-2017
Curcumin formula shows promise against treatment-resistant childhood cancer
University of Central Florida
Attaching curcumin, a component of the common spice turmeric, to nanoparticles can be used to target and destroy treatment-resistant neuroblastoma tumor cells, according to a new study published in Nanoscale.
The study, conducted in partnership by researchers at Nemours Children’s Hospital and the University of Central Florida, demonstrates a potentially novel treatment for neuroblastoma, the most common cancer in infants.
“High-risk neuroblastoma can be resistant to traditional therapy, and survival can be poor. This research demonstrates a novel method of treating this tumor without the toxicity of aggressive therapy that can also have late effects on the patient’s health,” said Tamarah J. Westmoreland, MD, PhD, a pediatric surgeon at Nemours Children’s Health System and senior author of the study. “Unique approaches to target tumor cells with nanoparticle delivery systems hold promise for treatment of resistant tumors, such as the high risk neuroblastoma. We are hopeful that in the future, nanoparticles can be utilized to personalize care to patients and reduce the late effects of therapy.”
Neuroblastomas are cancers that start in early nerve cells and commonly form in the tissue of the adrenal glands, near the kidneys. About 700 new cases of neuroblastoma are diagnosed each year in the United States and most cases appear in children younger than 5 years old. High-risk neuroblastoma is hard to cure and is more likely to become resistant to standard therapies or recur. These cancers are also associated with late effects after treatments have ended, including developmental delays, hearing loss, or other disabilities.
Curcumin has been shown to have substantial anti-cancer ability, but its low solubility and poor stability have made its use in medicinal applications challenging. Researchers from Nemours and UCF found that nanoparticles can be used to deliver curcumin to tumor sites.
“This shows that nanoparticles can be an effective delivery vehicle for cancer drugs,” said Professor Sudipta Seal, who directs of UCF’s NanoScience Technology Center and Advanced Materials Processing Analysis Center, and is a collaborator on the study. “More research is needed, but we are hopeful it could lead to more effective treatment of this devastating disease in the future.”
In the study, researchers loaded Cerium oxide nanoparticles with curcumin and coated them with dextran to test in cell lines of a high-risk form of neuroblastoma, known as MYCN-amplified, as well as non-amplified neuroblastoma. This formulation induced substantial cell death in neuroblastoma cells while producing no or only minor toxicity in healthy cells. Overall, the nano-therapeutic treatments showed a more pronounced effect in MYCN-amplified cells, which are traditionally more resistant to drug therapies.
Nanoscience research, which explores the unusual properties of materials at the nanoscale, has led to advancements in medicine, energy, information storage, computing and other fields. At no more than 100 nanometers, nanoparticles are exceedingly small. By comparison, a sheet of paper is about 75,000 nanometers thick.
Public Release: 26-Jul-2017
New study shows that targeting calcium in the cell could lead to a new way to control cholesterol metabolism
University of Alberta Faculty of Medicine & Dentistry
(Edmonton) It’s well known that calcium is essential for strong bones and teeth, but new research shows it also plays a key role in moderating another important aspect of health–cholesterol.
Scientists at the University of Alberta and McGill University have discovered a direct link between calcium and cholesterol, a discovery that could pave the way for new ways of treating high blood cholesterol.
The researchers began the work after having their curiosity piqued while studying the role of a calcium-binding protein. They noticed an extreme rise of blood cholesterol concentration in mice when the protein was not present. To follow up on this observation, Marek Michalak with graduate student Wen-An Wang (University of Alberta) and Luis Agellon (McGill University) teamed up with geneticist Joohong Ahnn (Hanyang University, Korea) and discovered that the physiological link between calcium and cholesterol is also preserved in worms.
“There is a mechanism inside the cell that senses when there is not enough cholesterol present and turns on the machinery to make more,” said Michalak, a distinguished university professor in the University of Alberta’s Department of Biochemistry. “What we found is that a lack of calcium can hide cholesterol from this machinery. If you lose calcium, your synthetic machinery thinks there’s no cholesterol and it starts making more even if there is already enough.”
High blood cholesterol is a known risk factor for developing heart disease. “Factors that affect blood cholesterol concentration have been studied for a long time,” said Agellon, a professor at McGill’s School of Human Nutrition. “The general belief was that cholesterol controlled its own synthesis inside of cells, and then we discovered in our labs that calcium can control that function too. Finding this link potentially opens a door to developing new ways of controlling cholesterol metabolism.”
The researchers consider their finding a significant step toward developing different approaches to patient care in the future, but there is more work to be done. They are now looking to discover the common factor that allows calcium and cholesterol to communicate with each other in the cell and have received a four-year grant worth $456,000 from the Canadian Institutes of Health Research to continue their work.
This work was supported by the Canadian Institutes of Health Research grants MOP-15291, MOP-15415, MOP-53050 to M.M. ; MOP-15291 and MOP-86750 to L.B.A.; MOP-69043 to R.L.; and by the Basic Science Research Program from the National Research Foundation of Korea (NRF) (no. 2015R1D1A1A01059062 to S-K.L. and no. 2015R1D1A1A01058179 to J.A.). C. elegans strains were obtained from Caenorhabditis Genetics Center, which is funded by NIH Office of Research Infrastructure Program (P40 OD010440).
Loss of Calreticulin Uncovers a Critical Role for Calcium in Regulating Cellular Lipid Homeostasis, by Wen-An Wang et al., Scientific Reports
Public Release: 27-Jul-2017
Vitamin E-deficient embryos are cognitively impaired even after diet improves
Oregon State University
CORVALLIS, Ore. – Zebrafish deficient in vitamin E produce offspring beset by behavioral impairment and metabolic problems, new research at Oregon State University shows.
The findings are important because the neurological development of zebrafish is similar to that of humans, and nutrition surveys indicate roughly 95 percent of women in the U.S. have inadequate intakes of this critical micronutrient.
The problem may be exacerbated in women of child-bearing age who avoid high-fat foods and may not have a diet rich in oils, nuts and seeds, which are among the foods with the highest levels of vitamin E, an antioxidant necessary for normal embryonic development in vertebrates.
Corresponding author Maret Traber and collaborators at OSU compared offspring from fish on vitamin E-deficient diets – the E-minus group – with those on vitamin E-adequate diets, the E-plus fish.
The E-minus embryos had more deformities and greater incidence of death as well as an altered DNA methylation status through five days after fertilization; five days is the time it takes for a fertilized egg to become a swimming zebrafish.
For the next seven days, all of the normal-looking fish, irrespective of diet history, were fed a vitamin E-adequate diet.
Both groups grew normally and showed similar DNA methylation, but the E-minus fish failed to learn and were afraid. They also continued to have metabolic defects and indications of mitochondrial damage.
Because insufficient vitamin E reached the E-minus embryos’ brains, those brains continued to lack choline and glucose and simply did not develop correctly, said Traber, a professor in the OSU College of Public Health and Human Sciences, and Ava Helen Pauling Professor in the Linus Pauling Institute.
“They managed to get through the critical period to get the brain formed, but they were stupid and didn’t learn and didn’t respond right,” Traber said. “They had so much oxidative damage they essentially had a screwed-up metabolism. These outcomes suggest embryonic vitamin E deficiency in zebrafish causes lasting impairments that aren’t resolved via later dietary vitamin E supplementation.
“What that means for people is that many people are walking around with inadequate intakes, and how is their metabolism being affected and especially the brain, which is highly polyunsaturated and has specific mechanisms for retaining vitamin E? It takes awhile to get vitamin E into the brain to protect it, and this has me concerned about teenage girls who eat inadequate diets and get pregnant.”
Traber said a lack of vitamin E causes a chain reaction that dramatically changes cell metabolism.
“It’s the secondary ripples of having inadequate vitamin E that are really causing the problems, and it takes a fair amount of time to correct all of those things that go wrong,” she said. “It’s very frightening is what it really comes down to.”
Traber’s collaborators included OSU colleagues Melissa McDougall, Jaewoo Choi, Lisa Truong and Robert Tanguay.
Findings were recently published in Free Radical Biology and Medicine. The National Institutes of Health and the National Institute of Environmental Health Sciences supported this research.
Public Release: 28-Jul-2017
New research in The FASEB Journal identifies potential therapeutic intervention for memory impairment, neuroinflammation, and brain insulin resistance induced by high-fat, high-fructose diet
Federation of American Societies for Experimental Biology
A study published online in The FASEB Journal, involving mice, suggests that EGCG (epigallocatechin-3-gallate), the most abundant catechin and biologically active component in green tea, could alleviate high-fat and high-fructose (HFFD)-induced insulin resistance and cognitive impairment. Previous research pointed to the potential of EGCG to treat a variety of human diseases, yet until now, EGCG’s impact on insulin resistance and cognitive deficits triggered in the brain by a Western diet remained unclear.
“Green tea is the second most consumed beverage in the world after water, and is grown in at least 30 countries,” said Xuebo Liu, Ph.D., a researcher at the College of Food Science and Engineering, Northwest A&F University, in Yangling, China. “The ancient habit of drinking green tea may be a more acceptable alternative to medicine when it comes to combatting obesity, insulin resistance, and memory impairment.”
Liu and colleagues divided 3-month-old male C57BL/6J mice into three groups based on diet: 1) a control group fed with a standard diet, 2) a group fed with an HFFD diet, and 3) a group fed with an HFFD diet and 2 grams of EGCG per liter of drinking water. For 16 weeks, researchers monitored the mice and found that those fed with HFFD had a higher final body weight than the control mice, and a significantly higher final body weight than the HFFD+EGCG mice. In performing a Morris water maze test, researchers found that mice in the HFFD group took longer to find the platform compared to mice in the control group. The HFFD+EGCG group had a significantly lower escape latency and escape distance than the HFFD group on each test day. When the hidden platform was removed to perform a probe trial, HFFD-treated mice spent less time in the target quadrant when compared with control mice, with fewer platform crossings. The HFFD+EGCG group exhibited a significant increase in the average time spent in the target quadrant and had greater numbers of platform crossings, showing that EGCG could improve HFFD-induced memory impairment.
“Many reports, anecdotal and to some extent research-based, are now greatly strengthened by this more penetrating study,” said Thoru Pederson, Ph.D., Editor-in-Chief of The FASEB Journal.
Public Release: 2-Aug-2017
American Chemical Society
An ice cold drink is refreshing in the summer, but for people with sensitive teeth, it can cause a painful jolt in the mouth. This condition can be treated, but many current approaches don’t last long. Now researchers report in the journal ACS Applied Materials & Interfaces the development of a new material with an extract from green tea that could fix this problem — and help prevent cavities in these susceptible patients.
Tooth sensitivity commonly occurs when the protective layers of teeth are worn away, revealing a bony tissue called dentin. This tissue contains microscopic hollow tubes that, when exposed, allow hot and cold liquids and food to contact the underlying nerve endings in the teeth, causing pain. Unprotected dentin is also vulnerable to cavity formation. Plugging these tubes with a mineral called nanohydroxyapatite is a long-standing approach to treating sensitivity. But the material doesn’t stand up well to regular brushing, grinding, erosion or acid produced by cavity-causing bacteria. Cui Huang and colleagues wanted to tackle sensitivity and beat the bacteria at the same time.
The researchers encapsulated nanohydroxyapatite and a green tea polyphenol — epigallocatechin-3-gallate, or EGCG — in silica nanoparticles, which can stand up to acid and wear and tear. EGCG has been shown in previous studies to fight Streptococcus mutans, which forms biofilms that cause cavities. Testing on extracted wisdom teeth showed that the material plugged the dentin tubules, released EGCG for at least 96 hours, stood up to tooth erosion and brushing and prevented biofilm formation. It also showed low toxicity. Based on these findings, the researchers say the material could indeed be a good candidate for combating tooth sensitivity and cavities.