Lymphocytes of type 2 diabetic women carry a high load of stablechromosomal aberrations: a novel risk factor for disease-relatedearly death.
OBJECTIVE—Diabetes is associated with an increased risk of death in women. Oxidative stress due to chronic hyperglycemia leads to the generation of reactive oxygen species and loss of chromosomal integrity. To clarify whether diabetes is a premature aging syndrome, we determined telomere erosion dynamics and occurrence of structural chromosomal aberrations in women of the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study. RESEARCH DESIGN AND METHODS—Telomere lengths and karyotypes were examined in peripheral blood mononuclear cells. Regarding these parameters, surviving and deceased type 2 diabetic women of the LURIC study were compared with nondiabetic LURIC women with or without coronary heart disease and with healthy female control subjects. RESULTS—Significantly enhanced telomere attrition was seen in all LURIC subjects compared with healthy control subjects. Although the average telomere-length loss is equivalent to well >10 years of healthy aging, telomere erosion was not associated with outcome within the LURIC cohort. However, strikingly high numbers of stable chromosomal aberrations were found in type 2 diabetic women but not in LURIC disease control subjects or in healthy individuals. Furthermore, within the younger age- groups, deceased type 2 diabetes patients had significantly more marker chromosomes than the surviving type 2 diabetic patients. CONCLUSIONS—All women at high risk for cardiovascular death have accelerated telomere erosion, not caused by type 2 diabetes per se but likely linked to other risk factors, including dyslipidemia. By contrast, the occurrence of marker chromosomes is associated with type 2 diabetes and is a novel risk factor for type 2 diabetes–related early death. Type 2 diabetes is characterized by increased morbidity and all-cause mortality (1,2). The combination of excess caloric intake and reduced physical activity leading to obesity, dyslipidemia, and hypertension increases the risk for diabetes and coronary heart disease (CHD). Recent data show that among diabetic men, the mortality rate has decreased significantly, whereas in diabetic women, no such trend was found (3). The all-cause mortality rate difference between diabetic and nondiabetic women is considerable. Therefore, the combination of diabetes with multiple risk factors identifies women at particularly high risk (2,4). The relative risk for morbidity and mortality in women with diabetes is increased compared with nondiabetic control subjects (2,5). Diabetes may therefore be regarded as a premature aging syndrome in which the overall metabolic shift leads to genotoxic stress that results in loss of chromosomal integrity (rev. in 6). Oxidative stress plays a crucial role in the pathogenesis of type 2 diabetes and in diabetes-associated complications. The generation of reactive oxygen species (ROS) is a common downstream mechanism whereby multiple by-products of glucose and (pro)inflammatory molecules exert adverse effects (7–11). DNA damage and telomere attrition can serve as markers of these processes and, consequently, mirror the pace of biological aging (rev. in 12–14). Hypothesizing along these lines, we studied telomere erosion dynamics and/or the occurrence of structural chromosomal aberrations in women with type 2 diabetes who were participants of the Ludwigshafen Risk and Cardiovascular Health (LURIC) prospective cohort study (15). Life expectancy within the LURIC female cohort falls short by ∼10 years compared with the general female population in Germany. Telomeric erosion was much further advanced in all LURIC women, irrespective of type 2 diabetes, compared with age-matched control subjects, the difference amounting to >10 life-years. We further found a strikingly enhanced number of structural chromosomal aberrations in the peripheral lymphocytes of women with type 2 diabetes that was diabetes specific and, within the younger age-groups, associated with mortality.