Leukocyte telomere length is associated with high-risk plaques on virtual histology intravascular ultrasound and increased proinflammatory activity

Cellular aging and restorative processes: subjective sleep quality and duration moderate the association between age and telomere length in a sample of middle-aged and older adults

STUDY OBJECTIVES

To examine whether subjective sleep quality and sleep duration moderate the association between age and telomere length (TL).

DESIGN

Participants completed a demographic and sleep quality questionnaire, followed by a blood draw.

SETTING

Social Neuroscience Laboratory.

PARTICIPANTS

One hundred fifty-four middle-aged to older adults (age 45-77 y) participated. Participants were excluded if they were on immunosuppressive treatment and/or had a disease with a clear immunologic (e.g., cancer) component.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Subjective sleep quality and sleep duration were assessed using the Pittsburgh Sleep Quality Index (PSQI) and TL was determined using peripheral blood mononuclear cells (PBMCs). There was a significant first-order negative association between age and TL. Age was also negatively associated with the self-reported sleep quality item and sleep duration component of the PSQI. A significant age × self-reported sleep quality interaction revealed that age was more strongly related to TL among poor sleepers, and that good sleep quality attenuated the association between age and TL. Moreover, adequate subjective sleep duration among older adults (i.e. greater than 7 h per night) was associated with TL comparable to that in middle-aged adults, whereas sleep duration was unrelated to TL for the middle-aged adults in our study.

CONCLUSIONS

The current study provides evidence for an association between sleep quality, sleep duration, and cellular aging. Among older adults, better subjective sleep quality was associated with the extent of cellular aging, suggesting that sleep duration and sleep quality may be added to a growing list of modifiable behaviors associated with the adverse effects of aging.

Telomeres and cardiovascular disease risk: an update 2013

Leukocyte telomere length (LTL) has been regarded as a potential marker of biologic aging because it usually shortens in a predictable way with age. Recently, a growing interest in cardiovascular aging has led to a number of new epidemiologic studies investigating LTL in various disease conditions. Some methodological problems exist because there are different methods available to determine LTL, and standardization is much needed. For example, in the majority of studies, patients with early-onset coronary heart disease have been shown to have shorter LTL. In addition, patients with diabetes mellitus complications tend to have shorter LTL than control subjects. On the other hand, increased left ventricular hypertrophy or mass is associated with longer LTL, and studies investigating hypertension have reported both shorter and longer LTL than found in normotensive control subjects. There is, therefore, a need for longitudinal studies to elucidate these complicated relationships further, to provide estimations of telomere attrition rates, and to overcome analytical problems when only cross-sectional studies are used. The understanding of cardiovascular aging and telomere biology may open up new avenues for interventions, such as stem cell therapy or agents that could retard this aging process over and beyond conventional risk factor control.

The history of sleep apnea is associated with shorter leukocyte telomere length: the Helsinki Birth Cohort Study

OBJECTIVES

Sleep apnea poses an elevated risk for chronic age-related diseases. Leukocyte telomere length (LTL), a biomarker and factor associated with accelerated cellular aging processes, may serve as a novel mechanism underlying these disease risks. We investigated if a history of clinician-diagnosed sleep apnea or primary snoring was associated with LTL in later adulthood.

METHODS

Data on sleep apnea, primary snoring and LTL, were available for 1948 participants from the Helsinki Birth Cohort Study. Patients with sleep apnea (n=44) and primary snoring (n=29) severe enough to be recorded as an inpatient diagnosis for hospitalization were identified by their case records through the Finnish Hospital Discharge Register. The LTL was measured by using the realtime quantitative polymerase chain reaction (PCR) method at a mean age of 61.5 years (standard deviation [SD], 2.9).

RESULTS

A history of sleep apnea was associated with shorter LTL (P=.010). Adjustment for a number of covariates did not alter the association.

CONCLUSIONS

Accelerated cellular aging reflected in shorter LTL in patients with a history of sleep apnea may partly explain their higher risk for age-related diseases. Future studies elucidating the impacts of long-term or successful treatment history of sleep apnea on the maintenance of LTL are warranted.

Infection duration and inflammatory imbalance are associated with atherosclerotic risk in HIV-infected never-smokers independent of antiretroviral therapy

OBJECTIVES

To determine whether the reported increased atherosclerotic risk among HIV-infected individuals is related to antiretroviral therapy (ART) or HIV infection, whether this risk persists in never-smokers, and whether inflammatory profiles are associated with higher risk.

DESIGN

Matched cross-sectional study.

METHODS

A total of 100 HIV-infected patients (50 ART-treated >4 years, 50 ART-naive but HIV-infected >2 years) and 50 HIV-negative controls were recruited in age-matched never-smoking male triads (mean age 40.2 years). Carotid intima-media maximal thickness (c-IMT) was measured across 12 sites. Pro-inflammatory [highly sensitive C-reactive protein (hs-CRP), resistin, interleukin-6, interleukin-18, insulin, serum amyloid A, D-dimer) and anti-inflammatory (total and high molecular weight adiponectin, interleukin-27, interleukin-10) markers were dichotomized into high/low scores (based on median values). c-IMT was compared across HIV/treatment groups or inflammatory profiles using linear regression models adjusted for age, diabetes, hypertension, and, for HIV-infected patients, nadir CD4 cell counts.

RESULTS

Although adjusted c-IMT initially tended to be thicker in ART-exposed patients (P=0.2), in post-hoc analyses stratifying by median HIV duration we observed significantly higher adjusted c-IMT in patients with longer (>7.9 years: 0.760±0.008 mm) versus shorter prevalent duration of known HIV infection (<7.9 years: 0.731±0.008 mm, P=0.02), which remained significant after additionally adjusting for ART (P=0.04). Individuals with low anti-inflammatory profile (<median versus >median score) had thicker c-IMT (0.754±0.006mm versus 0.722±0.006 mm, P<0.001), with anti-inflammatory markers declining as prevalent duration of HIV infection increased (P for linear trend <0.001).

CONCLUSION

Known HIV duration is related to thicker c-IMT, irrespective of ART, in these carefully selected age-matched never-smoking HIV-treated and ART-naive male individuals. Higher levels of anti-inflammatory markers appeared protective for atherosclerosis.

Mitochondrial DNA damage can promote atherosclerosis independently of reactive oxygen species through effects on smooth muscle cells and monocytes and correlates with higher-risk plaques in humans

BACKGROUND

Mitochondrial DNA (mtDNA) damage occurs in both circulating cells and the vessel wall in human atherosclerosis. However, it is unclear whether mtDNA damage directly promotes atherogenesis or is a consequence of tissue damage, which cell types are involved, and whether its effects are mediated only through reactive oxygen species.

METHODS AND RESULTS

mtDNA damage occurred early in the vessel wall in apolipoprotein E-null (ApoE(-/-)) mice, before significant atherosclerosis developed. mtDNA defects were also identified in circulating monocytes and liver and were associated with mitochondrial dysfunction. To determine whether mtDNA damage directly promotes atherosclerosis, we studied ApoE(-/-) mice deficient for mitochondrial polymerase-γ proofreading activity (polG(-/-)/ApoE(-/-)). polG(-/-)/ApoE(-/-) mice showed extensive mtDNA damage and defects in oxidative phosphorylation but no increase in reactive oxygen species. polG(-/-)/ApoE(-/-) mice showed increased atherosclerosis, associated with impaired proliferation and apoptosis of vascular smooth muscle cells, and hyperlipidemia. Transplantation with polG(-/-)/ApoE(-/-) bone marrow increased the features of plaque vulnerability, and polG(-/-)/ApoE(-/-) monocytes showed increased apoptosis and inflammatory cytokine release. To examine mtDNA damage in human atherosclerosis, we assessed mtDNA adducts in plaques and in leukocytes from patients who had undergone virtual histology intravascular ultrasound characterization of coronary plaques. Human atherosclerotic plaques showed increased mtDNA damage compared with normal vessels; in contrast, leukocyte mtDNA damage was associated with higher-risk plaques but not plaque burden.

CONCLUSIONS

We show that mtDNA damage in vessel wall and circulating cells is widespread and causative and indicates higher risk in atherosclerosis. Protection against mtDNA damage and improvement of mitochondrial function are potential areas for new therapeutics.

TERT's role in colorectal carcinogenesis

Telomerase reverse transcriptase (TERT) is one of the main functional subunits of the telomerase enzyme, which functions to increase telomere length. Studies have suggested that TERT may be important to the etiology of colorectal cancer. In this study we evaluate seven TERT SNPs in 1555 incident colon cancer cases and 1956 matched controls and in 754 incident rectal cancer cases and 959 matched controls. We observed that two TERT SNPs were associated with colon cancer. TERT rs2736118 was associated with increased risk of colon cancer (OR = 1.31, 95% CI 1.02, 1.69) and TERT-CLPTM1L rs2853668 was inversely associated with colon cancer (OR = 0.71, 95% CI 0.55, 0.92). TERT-CLPTM1L rs2853668 also was inversely associated with rectal cancer (OR 0.62, 95% CI 0.43, 0.90). BMI interacted significantly with three TERT SNPs to alter risk of colon cancer. Those with the variant allele and who were obese had the greatest risk of colon cancer. TERT-CLPTM1L rs2853668 interacted significantly with aspirin/NSAID use, where those with the AA genotype had a much lower risk of colon cancer when using aspirin/NSAIDs than those with the other genotypes. Several TERT SNPs were uniquely associated with CIMP+ and MSI tumors. These data confirm earlier reports of the association between TERT-CLPTM1L and colon and rectal cancer. Our detection of a significant interaction with BMI for multiple TERT SNPs and unique associations with CIMP+ tumors enhance our understanding of TERT's role in colon carcinogenesis.

[Effects of Chinese herbal medicine Shoushen Granule on telomere length and telomerase activity of peripheral white blood cells and vascular cells in rats with atherosclerosis]

OBJECTIVE

To observe the effects of Shoushen Granule, a compound traditional Chinese herbal medicine, on telomere length and telomerase activity in peripheral leukocytes and vascular cells, artery wall lesions and blood lipid in a Sprague-Dawley (SD) rat model of atherosclerosis.

METHODS

Forty SD rats were randomly divided into normal control group, model group, Shoushen Granule group and Western medicine group with 10 in each group. The rat model of atherosclerosis was established by high-fat diet and vitamin D3 loading. The model group was given gastric perfusion of double distilled water; The Shoushen Granule group and the Western medicine group were respectively given gastric perfusion of Shoushen Granule and pravastatin. After 12 weeks, pathological changes of abdominal aorta were determined by hematoxylin and eosin staining. Biochemical colorimetric method was used to detect the contents of total cholesterol (TC), triacylglycerol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol (LDL-C) in serum of the rats. Telomere length and telomerase activity in peripheral leukocytes and vascular cells of the rats were tested by quantitative real-time polymerase chain reaction method.

RESULTS

When compared with the model group, atherosclerosis lesions of the arterial wall were significantly improved in the Shoushen Granule group. In addition, both TC and LDL-C levels in the Shoushen Granule group were decreased significantly compared with the model group (P<0.01). Besides, not only telomerase activity but also telomere length in peripheral leukocytes (P<0.01) and vascular cells (P<0.05) were increased significantly as compared to those in the model group. However, there was no significant difference between the Shoushen Granule group and the normal control group (P>0.05).

CONCLUSION

Shoushen Granule improves the atherosclerosis lesions in rats, and the mechanism may be related to regulating telomere length and telomerase activity.

Aging and atherosclerosis: mechanisms, functional consequences, and potential therapeutics for cellular senescence

Atherosclerosis is classed as a disease of aging, such that increasing age is an independent risk factor for the development of atherosclerosis. Atherosclerosis is also associated with premature biological aging, as atherosclerotic plaques show evidence of cellular senescence characterized by reduced cell proliferation, irreversible growth arrest and apoptosis, elevated DNA damage, epigenetic modifications, and telomere shortening and dysfunction. Not only is cellular senescence associated with atherosclerosis, there is growing evidence that cellular senescence promotes atherosclerosis. This review examines the pathology of normal vascular aging, the evidence for cellular senescence in atherosclerosis, the mechanisms underlying cellular senescence including reactive oxygen species, replication exhaustion and DNA damage, the functional consequences of vascular cell senescence, and the possibility that preventing accelerated cellular senescence is a therapeutic target in atherosclerosis.

Accelerated aging as evidenced by increased telomere shortening and mitochondrial DNA depletion in patients with type 2 diabetes

Although shortened telomeres were shown associated with several risk factors of diabetes, there is lack of data on their relationship with mitochondrial dysfunction. Therefore, we compared the relationship between telomere length and mitochondrial DNA (mtDNA) content in patients with type 2 diabetes mellitus (T2DM; n = 145) and in subjects with normal glucose tolerance (NGT; n = 145). Subjects were randomly recruited from the Chennai Urban Rural Epidemiology Study. mtDNA content and telomere length were assessed by Real-Time PCR. Malonodialdehyde, a marker of lipid peroxidation was measured by thiobarbituric acid reactive substances (TBARS) using fluorescence methodology. Adiponectin levels were measured by radioimmunoassay. Oxidative stress as determined by lipid peroxidation (TBARS) was significantly (p < 0.001) higher in patients with T2DM compared to NGT subjects. In contrast, the mean telomere length, adiponectin and mtDNA content were significantly (p < 0.001) lower in patients with T2DM compared to NGT subjects. Telomere length was positively correlated with adiponectin, HDL, mtDNA content and good glycemic/lipid control and negatively correlated with adiposity and insulin resistance. On regression analysis, shortened telomeres showed significant association with T2DM even after adjusting for waist circumference, insulin resistance, triglyceride, HDL, adiponectin, mtDNA & TBARS. mtDNA depletion showed significant association with T2DM after adjusting for waist circumference and adiponectin but lost its significance when further adjusted for telomere length, TBARS and insulin resistance. Our study emphasizes the clustering of accelerated aging features viz., shortened telomeres, decreased mtDNA content, hypoadiponectinemia, low HDL, and increased oxidative stress in Asian Indian type 2 diabetes patients.