Leukocyte telomere shortening in elderly Type2DM patients with previous myocardial infarction

Dept. of Molecular Pathology and Innovative Therapies, Polytechnic University of Marche, Ancona, Italy.
Atherosclerosis (Impact Factor: 3.99). 05/2009; 206(2):588-93. DOI: 10.1016/j.atherosclerosis.2009.03.034
Source: PubMed


We performed a cross-sectional study to examine the differences in leukocyte telomere length among three groups of subjects: patients with type 2 diabetes mellitus without history of previous myocardial infarction (Type2DM), patients with type 2 diabetes mellitus with evidence of previous myocardial infarction (Type2DM+MI), and healthy control subjects (CTR). The main objective of the present study is to investigate differences in telomere length between the studied groups of subjects, with the aim to clarify if telomere length could be a reliable marker associated with MI in Type2DM patients. Secondary end point is the identification of associations between leukocyte telomere length and selected variables related to glycemic control, pro-inflammatory status and lipidic profile.
A total of 272 elderly subjects, 103 Type2DM (mean age 70+/-4 years, 59% males), 65 Type2DM+MI (mean age 68+/-7 years, 68% males), and 104 CTR (mean age 69+/-7 years, 50% males) were studied. Telomere length, defined as T/S (Telomere-Single copy gene ratio), was determined in leukocytes by quantitative real-time polymerase chain reaction (real-time PCR)-based assay. Moreover, we assessed: (1) high sensitive C reactive protein (hsCRP), fibrinogen and plasminogen-activator inibitor-1 (PAI-1) as inflammatory markers; (2) fasting glucose, insulin, glycated haemoglobin (HbA1C) and waist-to-hip ratio as markers of glycemic control; (3) total-cholesterol, HDL-cholesterol and triglycerides as markers of lipidic profile, in all sample population. The use of statins and sulfonylurea, as well as the presence of some relevant diabetes complications (nephropathy and retinopathy) were also assessed.
Type2DM+MI elderly patients have leukocyte telomere lengths shorter than those of Type2DM (without MI) and healthy CTR. Moreover, glucose, HbA1C and waist-to-hip ratio, variables related to glycemic control, showed a significant inverse correlation with leukocyte telomeres length.

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Available from: Francesca Marchegiani
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    • "The association between TL and chronic diseases has mostly been studied in cross-sectional settings. In some studies published so far, a shorter leukocyte TL has been associated with T2DM or its risk factors [20]–[28]. T2DM can be prevented by changes in lifestyle in high-risk individuals as shown in the DPS [30], [31]. Therefore, in this study, we set out to investigate whether preventative measures affect leukocyte TL within the average follow-up of 4.5 years. "
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    ABSTRACT: Leukocyte telomere length (TL) is considered a biomarker for biological aging. Shortened TL has been observed in many complex diseases, including type 2 diabetes (T2DM). Lifestyle intervention studies, e.g. the Diabetes Prevention Study (DPS), have shown a decrease in the incidence of T2DM by promoting healthy lifestyles in individuals with impaired glucose tolerance (IGT). Our aim was to study in the DPS the influence of the lifestyle intervention on TL. TL was measured by quantitative PCR-based method at two time points (N = 334 and 343) on average 4.5 years apart during the active intervention and post-intervention follow-up. TL inversely correlated with age. Our main finding was that TL increased in about two thirds of the individuals both in the intervention and in the control groups during follow-up; TL increased most in individuals with the shortest TL at the first measurement. TL was not associated with development of T2DM, nor did lifestyle intervention have an effect on TL. No association between insulin secretion or insulin resistance indices and TL was observed. We did not detect an association between TL and development of T2DM in the DPS participants. It could be due to all participants being overweight and having IGT at baseline, both of which have been found to be independently associated with shorter leukocyte TL in some earlier studies. TL had no substantial role in worsening of glucose tolerance in people with IGT. Our study confirms that leukocyte TL can increase with time even in obese people with impaired glucose metabolism.
    Full-text · Article · Apr 2012 · PLoS ONE
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    • "Epidemiology studies have identified a number of classic risk factors for type 2 diabetes, including age, obesity, and unhealthy lifestyles. Recently, several cross-sectional studies suggested that shorter telomeres correlate not only with the risk of type 2 diabetes but also with its complications, such as microalbuminuria and myocardial infarction (2–4). Experimental evidence showed that DNA damage responses and cellular senescence induced by telomere dysfunction led to increased reactive oxygen species (ROS) in fat cells, which ultimately resulted in the activation of p53, inflammation responses, and the promotion of insulin resistance (5). "
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    ABSTRACT: Recent studies have identified a set of serological markers for telomere dysfunction and DNA damage. The relevance of these serological markers in type 2 diabetes remains elusive. We investigated the association of serological markers (elongation factor 1α [EF-1α], stathmin, and N-acetyl-glucosaminidase) with leukocyte telomere length, a functional variant of uncoupling protein-2 (UCP2), and susceptibility of type 2 diabetes. A total of 930 patients and 867 control subjects were recruited to examine the association between leukocyte telomere length, UCP2 variant (-886G>A), recently identified serological markers, and type 2 diabetes. Telomere length was determined by a quantitative real-time PCR-based assay. EF-1α, stathmin, and C-reactive proteins were measured by enzyme-linked immunosorbent assays. N-acetyl-glucosaminidase was measured by an enzyme activity assay. The UCP2 variant was determined by PCR and restriction enzyme digestion. The average telomere length of type 2 diabetic patients was significantly shorter than that of control subjects. Serological N-acetyl-glucosaminidase correlates with both age and telomere length and was significantly higher in patients than in control subjects. Neither EF-1α nor stathmin showed significant difference between patients and control subjects. The UCP2-886G>A variant correlated with type 2 diabetes status but did not correlate with telomere length or the serological markers. Multivariate analysis showed that higher serological N-acetyl-glucosaminidase, shorter telomeres, and the UCP2-886G>A variant are independent risk factors for type 2 diabetes. Serological N-acetyl-glucosaminidase, telomere length, and the UCP2-886G>A variant are independent risk factors for type 2 diabetes. Serological N-acetyl-glucosaminidase correlates with telomere length but not with the UCP2-886G>A variant.
    Full-text · Article · Aug 2011 · Diabetes care
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    • "Telomere length is a polymorphic trait, and short telomeres are a uniquely inherited genotype that can cause degenerative disease even when telomerase is wild-type [17]. In recent cross-sectional studies, short telomeres have been associated with type 2 diabetes [31], [32], [33], [34]. Our data indicate that short telomeres are not simply associated with, but are a relevant modifier of diabetes risk and severity, and may be a valuable biomarker that identifies individuals at greatest risk in clinical settings. "
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    ABSTRACT: The genetic factors that underlie the increasing incidence of diabetes with age are poorly understood. We examined whether telomere length, which is inherited and known to shorten with age, plays a role in the age-dependent increased incidence of diabetes. We show that in mice with short telomeres, insulin secretion is impaired and leads to glucose intolerance despite the presence of an intact β-cell mass. In ex vivo studies, short telomeres induced cell-autonomous defects in β-cells including reduced mitochondrial membrane hyperpolarization and Ca(2+) influx which limited insulin release. To examine the mechanism, we looked for evidence of apoptosis but found no baseline increase in β-cells with short telomeres. However, there was evidence of all the hallmarks of senescence including slower proliferation of β-cells and accumulation of p16(INK4a). Specifically, we identified gene expression changes in pathways which are essential for Ca(2+)-mediated exocytosis. We also show that telomere length is additive to the damaging effect of endoplasmic reticulum stress which occurs in the late stages of type 2 diabetes. This additive effect manifests as more severe hyperglycemia in Akita mice with short telomeres which had a profound loss of β-cell mass and increased β-cell apoptosis. Our data indicate that short telomeres can affect β-cell metabolism even in the presence of intact β-cell number, thus identifying a novel mechanism of telomere-mediated disease. They implicate telomere length as a determinant of β-cell function and diabetes pathogenesis.
    Preview · Article · Mar 2011 · PLoS ONE
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