Alzheimer’s disease remains a mystery to the researchers. Scientists are doing their utmost, by analyzing the disease from the perspective of biochemistry, the potential impact of the environment or the education of patients. Their studies are extremely important, as the understanding of the pathogenesis of this complex disease might expand treatment options, perhaps prolong the lives of patients or at least improve it’s quality. Lately a new suspect has been introduced – dental X-rays.

Alzheimer’s disease is thought to be the most common cause of dementia among individuals over the age of 65. Although the probability of its occurrence increases with age, it is certainly not a natural consequence of aging. Statistics show that around 30 million people of the world’s population suffer from the consequences of this mysterious disease. Due to the progressive aging of the societies around the world, this number will triple over the next 40 years. The liberation of symptoms may be caused by genetic factors (genotype ApoEε4), environmental (smoking) and co-existing diseases (such as diabetes and hypertension).

Recent reports suggest a link between a frequent use of dental x-rays and Alzheimer’s disease. Proposed hypothesis says that X-rays destroy the telomeres of microglia, leading to premature aging and death of those cells. Telomeres protect the chromosome’s genetic material from damage during copying. Shortening of those structures is a natural consequence of cell divisions. Microglia – resident macrophages of the central nervous system – is essential to remove dying neurons and to perform the immune response. As a result of degeneration of the telomeres, the microglial cells lose their neuroprotective properties, leading to the death of neurons, thus consequently to dementia.

This hypothesis sheds new light on previously vague facts about Alzheimer’s disease. This explains in particular why there is such a long interval between the onset of histopathological changes in the brain (forming of Abeta plaques) and the presence of symptoms. Telomere damage would not affect the function of microglia directly, only would shorten its life. Only then after the death of microglial cells a gradual death of the surrounding neurons would begin. The whole process would take about a decade.

Treatments designed to eliminate amyloid plaques also proved to be powerless in the aspect of progressive dementia. If the destruction of microglial telomeres is really the reason for the development of Alzheimer’s disease, stem cell therapy should be considered with the use of autologous bone marrow or dental pulp cells.

Although the amount of radiation during dental x-rays is not large, the fact that even small doses are already a serious threat to the cells, causing mutations or damage of the telomeres, is still disturbing. Even though modern dentistry could not exist without X-rays, perhaps limiting its use should be considered. Reports about the influence of ionizing radiation on the increased risk of thyroid cancer or meningioma appear in scientific journals every year.

Additional examinations of a disastrous influence of X-rays on patients at risk for Alzheimer’s disease should be prepared. Studies on laboratory rodents by exposing them to ionizing radiation and a subsequent studying the microglial telomeres could be an important step in a further evaluation of the hypothesis.

Written by: Maria Bilińska

Source:
1. Dental X-ray exposure and Alzheimer’s disease: a hypothetical etiological association. Med. Hypotheses. 2011;77(1):29-34. Epub 2011 Mar 31, Caroline C. Rodgers
2. Longstreth WT Jr, Phillips LE, Drangsholt M, Koepsell TD, Custer BS, Gehrels JA, et al. Dental x-rays and the risk of intracranial meningioma: a population-based case-control study. Cancer 2004;100(5):1026-34.
3. Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association
Volume 8, Issue 2 , Page e1, March 2012 “Are dental X-rays causing Alzheimer’s? Ten reasons to take a closer look Caroline Rodgers

Want to know more about Alzheimer’s disease? Watch on medtube.net: “Alzheimer disease – Histopathology – Brain”.