Health News
Live oral bacteria found in arterial plaque
By
Lindy McCollum-Brounley
GAINESVILLE, Fla. - Gum disease has been linked to hardening of the arteries for nearly a decade, and scientists have long fingered a gang of oral bacteria as the obvious suspects behind many cases of the vessel-clogging killer.
Now University of Florida researchers have cornered the bacterial ringleaders of gum disease inside human artery-clogging plaque - the first concrete evidence to place the pathogens at the heart of the circulatory crime scene. Their report appears in the current issue of Atherosclerosis, Thrombosis and Vascular Biology.
"Our finding is important because it has proved there are live periodontal bacteria in human atherosclerotic tissue," said study investigator Ann Progulske-Fox, Ph.D., a professor of oral biology at the UF College of Dentistry. "Now we can begin to understand how these bacteria contribute to the disease process."
The oral bacteria UF researchers found in the plaque, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans, are two of the most aggressive offenders in periodontal disease, the leading cause of adult tooth loss. Because of the strong association between periodontal and cardiovascular diseases, scientists have postulated for years that oral pathogens contribute to arterial damage that leads to heart attack or stroke, which kill nearly a million Americans a year. In fact, a recent study conducted elsewhere found a direct correlation between the amount of periodontal bacteria in the mouth and the formation of blockages in the carotid artery in the neck.
To reach the circulatory system, the bacteria have to breech the barrier between tissues in the mouth and the bloodstream, Progulske-Foxsaid. For patients with periodontal disease, whose gums are inflamed and bleed easily, bristles from even the softest toothbrush can tear tiny blood vessels in the compromised gum tissues, leaving the door wide open for bacteria to enter.
But could the bacteria elude the body's protective immune response once within the bloodstream?
Researchers worldwide have sought to empirically nab oral bacteria - dead or alive - in atherosclerotic tissues. They have found remnants of bacterial DNA in arteries, signaling that bacteria had entered the bloodstream. Yet scientists have never been able to grow periodontal bacteria isolated from arterial plaque in Petri dishes, even though the same species of bacteria swabbed from oral plaque can be cultured that way. Therefore, researchers could not be sure the DNA was from bacterial trespassers destroyed by the immune system in the bloodstream, or if live bacteria were actually directly involved in plaque formation within the vessel walls.
"It makes sense that those periodontal bacteria most invasive in the mouth could be able to adapt to the vascular situation," said study project leader Emil Kozarov, Ph.D., an adjunct associate professor of oral biology at UF and a faculty member at Nova Southeastern University.
Probably only a handful of periodontal bacteria have been successful in making the jump of being infectious to both the oral and vascular tissues. Identifying these bacteria would give researchers the inside scoop on how the bacteria may contribute to cardiovascular disease, said Kozarov.
To find them, Progulske-Fox's team took the unusual approach of attempting to grow bacteria from arterial plaque directly on human artery cells. They obtained a section of a diseased carotid artery from a 74-year-old, partially toothless male patient undergoing surgery to remove an 80 percent blockage at Shands at UF in Gainesville. After removal, the sample was rinsed and placed on ice, then rushed to Progulske-Fox's nearby lab in a sealed, sterile container.
Within six hours of leaving the operating room, researchers pureed plaque from the artery and set it to incubate in a brew of healthy arterial cells and liquid growth medium. After 24 hours, the cells were separated from the slurry in the flask, washed several times, then subjected to a series of fluorescent baths containing antibodies sensitive to P. gingivalis and A. actinomycetemcomitans bacteria.
Finally, the cells were fixed to a glass slide and placed under a microscope to search for the presence of invasive periodontal bacteria within the cell structures. If any of the artery cells were infected with the bacteria, fluorescent antibodies would light them up like Alcatraz in lockdown.
Progulske-Fox and her team found the endothelial cells were infected with both P. gingivalis and A. actinomycetemcomitans, proving live bacteria had been present in the atherosclerotic plaque.
"This report certainly provides a smoking gun that live bacteria have become seeded from the oral cavity to become inhabitants of the vessel wall," said Steve Offenbacher, D.D.S., Ph.D., distinguished professor of periodontology at the University of North Carolina at Chapel Hill School of Dentistry. "The exciting implications focus on the known ability of these bacteria to destroy connective tissue in the mouth, suggesting that when infecting the vessel wall they may contribute to the instability of the atherosclerotic plaque - leading to acute events such as heart attack or stroke."
Progulske-Fox plans to study atherosclerotic tissue samples from 50 to 60 more patients to better understand how bacteria infect arterial cells. She suspects some strains of the bacteria may be more successful in breaching the barriers separating oral tissues from the bloodstream. These bad bugs would become "most wanted" in the fight against periodontal and cardiovascular disease.
"More study samples will show us which strains are implicated in the disease process, so we can design simple diagnostic technology that could be used in a dental office to identify specific bacteria the patient is carrying and whether that bacteria is known to cause atherosclerotic disease," said Progulske-Fox.
She envisions those diagnostic tests would be the first step in the war against periodontal and cardiovascular diseases, eventually leading to the development of a vaccine that would prevent oral bacteria from ever gaining a stronghold in the mouth. Antibiotic or antimicrobial treatments that could kill the bacteria after they have entered the circulatory system might also someday be possible.
For now, however, she advises people to practice good oral hygiene. "It is important for these patients to have very good dental hygiene," said Progulske-Fox, "because losing a tooth may not be a big deal to some people, but it can become a life-threatening situation."
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Autistic kids benefit from dads' involvement
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By Tracy Brown Wright
GAINESVILLE, Fla. - Make room for daddy, say University of Florida autism experts. Teaching fathers how to communicate and play with their autistic children pays dividends, for parents and kids alike.
Autism is a developmental disability that typically appears during the first three years of life and is characterized by problems interacting and communicating with others. Caring for an autistic child can be a relentless and labor-intensive task - one that is overwhelmingly performed by mothers, says UF nursing researcher Jennifer Elder, Ph.D., R.N.
Now UF researchers have found that teaching fathers how to talk to and play with their autistic children in a home setting improved communication, increased the number of intelligible words the youngsters spoke by more than 50 percent and helped dads get more involved in their care. The findings were published in a recent issue of the journal Nursing Research.
"We found that fathers were getting frustrated because they felt they couldn't connect with their autistic child," said Elder, the study's principal investigator and an associate professor and chairwoman of the department of health care environments and systems at UF's College of Nursing. "During one of our sessions, a child made eye contact with his father and said 'Daddy' for the first time in the child's life.
"Traditionally, mothers are the primary caretakers of autistic children," Elder added. "Through our training, we caused a shift in the paradigm of many of these families, with fathers taking on a more active role with their autistic children, sometimes even taking the lead in caretaking."
At least 1.5 million Americans have some form of autism, and it now affects one in every 166 births, according to the Centers for Disease Control and Prevention.
UF researchers examined 18 father-child relationships before and after specialized training sessions. The families were recruited through UF's Center for Autism and Related Disabilities and a community health practice in Central Florida and included 14 boys and four girls ranging in age from 3 years to 7 years old.
Building on a similar study of mothers of autistic children, Elder videotaped the father-child pairs in their homes during playtime sessions before training and at three key stages in the training process. The training emphasized language development and taught fathers to use everyday activities like playing with building blocks, puppets, cars and trucks, and bubbles to interact with their children.
UF researchers assessed each child's behavior and evaluated how fathers interacted with them at the beginning of the study and during each of the three training stages. They also recorded each child's autistic-like behaviors during and after play. During the first stage, fathers learned to initiate play with their children through animated repetition of their children's vocalizations and actions. Fathers were told to resist the temptation to direct their child's play and instead to follow the child's lead. In the second phase, they were told to wait for their child's response before continuing play. Eventually, the two techniques were used together.
The fathers were able to view the videotaped sessions to see their progress and areas needing improvement were discussed.
"We are really interested in promoting social balance, or turn-taking, in autistic children and their parents," Elder said. "Normally, the parent might cue the child with one question, ask another question without waiting, and the child gets very frustrated and starts not to even attempt to respond. To combat that, we teach the parents to give a cue and wait for the response, with the expectation that the child will respond to establish that social balance."
Fathers were more likely to initiate play in an animated way and responded more to their children during playtime. Children also became more vocal and were more than twice as likely to initiate play with their fathers. Surveys completed after the study was over also revealed that fathers viewed the training as valuable.
"One father related how after training, he felt empowered in his paternal role and became an active school liaison," Elder said. "This proved beneficial for the child, who now had both parents consistently involved in his education."
Researchers also were surprised to find that many fathers in the study actually took the lead in training the mothers and even siblings in the rest of the family, a key distinction from the mothers in her previous study, Elder said. In that study, researchers found similar benefits to training mothers, but moms weren't as likely to attempt to teach fathers the techniques they learned.
Recent research has shown that early intervention with children can have a major influence on how the child develops and functions later in life.
"With the proper training at an early age, we feel that these techniques can help autistic children be more socially interactive and pick up language more easily," Elder said.
Because of the study's small sample size, Elder and her research team plan to continue their research with a larger group of fathers and fine-tune the interventions used based on their experiences in this study. They also plan to show fathers how to train their spouses in the techniques, and then evaluate the effectiveness of that approach. In addition, they are developing a Web site so training "booster" sessions can be broadcast via the Internet to participating fathers. Fathers will be able to view these training sessions and hear comments on how to improve upon their play sessions with their children.
"It is important for both the child's mother and father to be involved in parent training whenever possible," said Jaime Winter, M.A., a research scientist at the University of Washington Autism Center who previously conducted autism research at the University of California-San Diego. "Potential benefits that may follow from father participation include increased frequency of interaction and quality of interaction between fathers and their child with autism, increased treatment time for the child and support for the child's mother."
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