Oral Health The Key To Alzheimer’s Cure?

To build a tooth, a detailed recipe to instruct cells to differentiate towards proper lineages and form dental cells is needed. Researchers in the group of Professor Irma Thesleff at the Institute of Biotechnology in Helsinki, Finland have now found a marker for dental stem cells. They showed that the transcription factor Sox2 is specifically expressed in stem cells of the mouse front tooth.
Despite the development of new bioengineering protocols, building a tooth from stem cells remains a distant goal. Demand for it exists as loss of teeth affects oral health, quality of life, as well as one’s appearance. To build a tooth, a detailed recipe to instruct cells to differentiate towards proper lineages and form dental cells is needed. However, the study of stem cells requires their isolation and a lack of a specific marker has hindered studies so far.
Researchers in the group of Professor Irma Thesleff at the Institute of Biotechnology in Helsinki, Finland have now found a marker for dental stem cells. They showed that the transcription factor Sox2 is specifically expressed in stem cells of the mouse incisor (front tooth). The mouse incisor grows continuously throughout life and this growth is fueled by stem cells located at the base of the tooth. These cells offer an excellent model to study dental stem cells.
The researchers developed a method to record the division, movement, and specification of these cells. By tracing the descendants of genetically labeled cells, they also showed that Sox2 positive stem cells give rise to enamel-forming ameloblasts as well as other cell lineages of the tooth.
– Although human teeth don’t grow continuously, the mechanisms that control and regulate their growth are similar as in mouse teeth. Therefore, the discovery of Sox2 as a marker for dental stem cells is an important step toward developing a complete bioengineered tooth. In the future, it may be possible to grow new teeth from stem cells to replace lost ones, says researcher Emma Juuri, a co-author of the study

A Danish–American study has proven that incidences of Alzheimer’s disease can be traced back to chronic gum inflammation. According to the research team, patients with periodontal disease are at an increased risk of poorer cognitive function.
Researchers presumed that periodontal infection exacerbates inflammation in the brain and thus worsens dementia. They thus hypothesized that subjects with periodontal infection are at an increased risk of developing Alzheimer’s disease.
The first long-term study to establish a causal link between the two diseases was conducted at New York University and led by Dr. Angela Kamer, assistant professor of Periodontology and Implant Dentistry, in collaboration with Dr. Douglas E. Morse, associate professor at NYU College of Dentistry and a team of researchers in Denmark.
Kamer had already explored the role of periodontitis in Alzheimer’s disease through a pilot study conducted in 2008. Patients with chronic infections of the gum typically display high levels of antibodies. Kamer thus examined 18 Alzheimer patients and determined whether they had elevated levels of antibodies compared with the 16 control subjects. The study revealed that twice as many subjects with Alzheimer’s disease tested positive for the respective periodontal antibodies in their plasma.
The latest study, however, was based on the analysis of data on inflammation and cognitive function in 152 Danish subjects, for whom measures were available for both periodontal inflammation (at age 70) and cognitive function (at ages 50 and 70). The time span taken into account covered a 20-year period ending in 1984, when the subjects had all reached the age of 70.
The Digit Symbol Test was used to assess the subjects’ cognition, a neuropsychological test also used to detect cases of brain damage and dementia, which rates patients’ IQ and ability to link series of digits to a corresponding list of digit–symbol pairs.
Comparing cognitive functions at ages 50 and 70, Kamer found that periodontal inflammation at age 70 was strongly associated with a lower test score at the age of 70. Subjects with inflammation were nine times more likely to have lower scores than subjects without periodontal inflammation.
Kamer concluded that the results of the analysis suggest that periodontal inflammation is associated with lower cognitive function in older people. The researchers considered the study’s findings to be important for presymptomatic early diagnosis of Alzheimer’s disease.
Kamer plans to conduct a follow-up study involving a more diverse group of subjects.
According to the study, more than 25 million people suffer from dementia worldwide, with 50 to 60 percent having Alzheimer’s disease.