Do short telomeres warn about diabetes?
Scientists have linked the length of telomeres with the risk of diabetes
LifeSciencesToday about Johns Hopkins Medicine: DNA 'End-Caps' Length Linked to Diabetes RiskAccording to Johns Hopkins University scientists, short telomeres – protective "caps" at the ends of chromosomes – may indicate a person's predisposition to the development of age-related diabetes.
These data were obtained as a result of a study conducted on mice with short telomeres.
Telomeres are repetitive DNA sequences that protect the ends of chromosomes. As the body ages, they usually become shorter. At the same time, the cells lose their ability to divide normally and eventually die. Telomere shortening is associated with cancer, lung diseases and other age-related diseases. Diabetes, also associated with aging, affects one in four adults over the age of 60.
A study by scientists from Johns Hopkins University, published in the journal PLoS One (Short Telomeres Compromise β-Cell Signaling and Survival), is based on the observation of Mary Armanios (Mary Armanios – she took the picture shown here, in which telomeres look like pink dots), who drew attention to the presence of a certain relationship between the incidence of diabetes and congenital dyskeratosis (dyskeratosis congenital) is a rare hereditary disease caused by a violation of the mechanism of maintaining telomere length. Patients with hereditary dyskeratosis often have premature gray hair and early insufficiency of many organs.
"Congenital dyskeratosis is a disease that essentially causes people to age prematurely. We knew that the incidence of diabetes increases with age, so we assumed that there may also be a connection between telomeres and diabetes," Armanios, associate professor of oncology at the Kimmel Cancer Center, comments on the study Johns Hopkins University.
Diabetic patients do not produce enough insulin, and their cells cannot use it effectively, which leads to a violation of the regulation of blood sugar levels.
Armanios studied mice with short telomeres and their insulin-producing beta cells. She found that despite the presence of a large number of healthy-looking beta cells, the blood sugar levels in these mice were higher, and the cells secreted two less insulin than in the control group animals.
"This corresponds to the early stages of diabetes in humans, when cells have difficulty releasing insulin in response to sugar," explains Armanios. "In these mice, at many stages of insulin secretion, from mitochondrial energy production to calcium signaling, the cells function at half their normal levels," Armanios says.
In the beta cells of mice with short telomeres, scientists found a violation of the regulation of the p16 gene associated with aging and diabetes. In addition, many genes of the pathways necessary for insulin secretion, including the pathway controlling calcium signaling, have been altered in them. No such errors were detected in the control group.
Some previous studies have shown that patients with diabetes may have short telomeres, but whether this increases the risk of developing diabetes or is a consequence of this disease remained unclear.
"Aging is the main risk factor for diabetes. In addition, family heredity plays a very important role. Telomere length is a hereditary factor and can make people more predisposed to developing diabetes," Armanios believes.
Based on this work, Armanios concludes that telomere length can serve as a biomarker for the development of diabetes. In the course of further research, scientists plan to find out whether it is possible to predict the risk of developing this disease based on the length of telomeres."
Portal "Eternal youth" http://vechnayamolodost.ru29.03.2011