Average Relative Telomere Length Research Articles

The relationship between relative telomere length and anti-tuberculosis drug-induced hepatitis : A case-control study

Anti-tuberculosis drug-induced hepatitis (AT-DIH) is a common and serious adverse drug reaction of tuberculosis treatment. Evidence demonstrated that many factors could affect the occurrence of AT-DIH, such as ageing, smoking, alcohol, oxidative stress, etc., while these factors could also promote telomere shortening. Therefore, relative telomere length (RTL) is indirectly related to the occurrence of AT-DIH. The present study aimed to explore and validate this relationship in Chinese tuberculosis patients. A 1:4 matched case-control study was undertaken using 202 AT-DIH cases and 808 controls. Logistic regression models were used to estimate the association between RTL and AT-DIH with odds ratios (ORs) and 95% confidence intervals (CIs). The area under receiver operating characteristic curve (AUC) was calculated to estimate the discriminative performance for distinguishing AT-DIH cases from controls. The average RTL in AT-DIH cases was significantly shorter than that in controls (1.24 vs. 1.46, P=0.002). Patients with longer RTL were at a reduced risk of AT-DIH (OR=0.79, 95% CI: 0.66-0.94, P=0.009), and a dose-response relationship also existed between RTL and lower AT-DIH risk (P for trend=0.012). Under the optimal RTL cut-off value of 1.22, the corresponding AUCs were 0.57 (95% CI: 0.53-0.62, P=0.001) in the univariate model and 0.62 (95% CI: 0.57-0.66, P<0.001) in the multivariate model. This study showed that the shorter the RTL, the higher the risk of AT-DIH during an anti-tuberculosis treatment. The short RTL could potentially serve as a risk factor or a predictive test of the hepatotoxic risk associated with anti-tuberculosis treatments.

Telomere length in individuals with early pregnancy losses

Aim. Over the past decade, telomere biology has become an important topic in the field of human reproduction.We focused on the relationship between relative telomere length (RTL) and tendency to early pregnancy loss (EPL) in humans. Methods. RTL was measured in DNA isolated from the blood samples using a real-time polymerase chain reaction approach. RTL was examined in control group (C) (N=209) – women (CW) (N=107) and men (CM) (N=102) who had healthy pregnancies with no history of infertility or miscarriage, and in group with EPL (N=445) – women (EPLW) (N=223) and men (EPLM) (N=212) who had single or more EPL. RTL data were analyzed by gender and reproductive history. Results. Women (CW+EPLW) have significantly higher RTL that men (CM+EPLM) (1.74±0.06 in women and 1.40±0.05 in men, P=0.000053). Average RTL were significantly lower in CM compared to CW (CW: 2.27±0.12 versus CM: 1.15±0.08, P=0.0000001), and were similar in EPLW and EPLM (1.50±0.06 in EPLW and 1.53±0.06 in EPLM, P=0.47). The EPLW group had significantly lower RTL than control (EPLW: 1.50±0.06 versus CW: 2.27±0.12, P=0.0000001). Average RTL were significantly lower in CM compared to EPLM (1.15±0.08 in CM and 1.53±0.06 in EPLM, P=0.00006). Conclusions. Women with no history of EPL have longer telomere than men. Woman with EPL have shorter telomere that women without miscarriage. In EPL group women and men have similar telomere length.Keywords: telomeres, RT-PCR, gender, early reproductive loss.

Довжина теломер у хворих на цукровий діабет 2-го типу та її зв’язок із метаболічним профілем

To study leukocyte telomere length and its relationship with metabolic profile 35 patients with metabolic syndrome and type 2 diabetes mellitus (T2DM) and 21 healthy people of middle age (35-59 years) were examined. The anthropometric characteristics of obesity, indicators of lipid and glucose metabolism, alanin aminotransferase (ALT) and high sensitive C-reactive protein levels were studied. The relative average telomere length was determined by the method of monochrome multiplex quantitative real time polymerase chain reaction. Patients with T2DM had higher BMI, waist circumference, higher high sensitive C-reactive protein, ALT and glucose levels and a worse lipid profile (p &lt;0.05). At the same time, the median telomere length did not differ between groups. Nevertheless, in the T2DM group the telomere length inversely correlated with body weight (r = –0.35; p &lt; 0.05), BMI (r = –0.36; p &lt; 0.05), waist circumference (r = –0.34; p &lt; 0.05) and ALT level (r = –0,44; p&lt;0,05) in contrast to healthy subjects. No relationship was found between the telomere length and the level of fasting glycemia, as well as the age of the participants of both groups. Thus, in T2DM patients increase in BMI, waist circumference and ALT level were associated with a shorter leukocyte telomere length. Despite the worse metabolic profile, the telomere length in middle-aged T2DM patients did not differ from that in the control group. This indicates that the leukocyte telomere length is influenced not only by the presence of T2DM and the metabolic profile indicators, but, obviously, by other factors as well.

Replicative senescence and arteriosclerosis after kidney transplantation.

Replicative senescence is associated with telomere shortening. In native kidneys, obtained prior to transplantation, we recently described and validated a significant association between shorter intrarenal telomere length and renal arteriosclerosis. After renal transplantation, animal experiments suggested that ischaemia-reperfusion injury, acute rejection episodes and cytomegalovirus disease associate with accelerated renal allograft senescence. The association between post-transplant events and replicative senescence has not yet been evaluated in a human setting. In a cohort of 134 kidney allograft recipients, we performed protocol-specified renal allograft biopsies at 3 months, 1 year, 2 years and 5 years after transplantation (n = 579 biopsies). We used quantitative real-time polymerase chain reaction to measure intrarenal relative average telomere length (T/S ratio). The association between donor and recipient demographic factors, post-transplant clinical/histological events, renal allograft histological evolution by 5 years post-transplant and intrarenal telomere length at 5 years after transplantation was studied using multiple regression models. At 5 years after transplantation, shorter intrarenal telomere length was associated with male donor gender, older donor age, donor history of hypertension and donor cardiovascular risk, which confirms the associations observed in native kidneys. Recipient characteristics and post-transplant events like delayed graft function, acute rejection episodes, presence of donor-specific antibodies, cytomegalovirus disease and immunosuppressive regimen did not associate with alterations of intrarenal telomere length at 5 years. Independent of donor age and donor cardiovascular risk, intrarenal arteriosclerosis in protocol biopsies obtained at 5 years after transplantation and progressive arteriosclerosis over time after transplantation associated with shorter telomere length, while this was not the case for other histological lesions. Moreover, telomere attrition augments the association between older donor age and the presence of severe arteriosclerosis. In the group with the oldest donor age and shortest telomere length, there was significantly more severe arteriosclerosis (43%) in protocol biopsies at 5 years after transplantation, compared with other combinations (13-28%) (P = 0.001). Intrarenal arteriosclerosis at 5 years after transplantation did not associate with post-transplant clinical events. We demonstrate that intrarenal telomere length at 5 years after transplantation, as a marker for replicative senescence, associates with renal arteriosclerosis and reflects kidney donor characteristics, but not post-transplant events.

Telomere lengths in women with early reproductive losses

Aim. Study of the relative telomere lengths in women with a history of early reproductive losses. Methods. Relative Telomere Length (RTL) was studied in the peripheral blood lymphocytes using a real time polymerase chain reaction (RT-PCR). Results. RTL was studied in 281 women, among which 169 - with early reproductive losses (ERL) (surveyed group) and 112 - have healthy children and no reproductive losses in history (control group). For women under the age of 35, the average RTL value is significantly higher than that of older women, P = 0.003597. In women with ERL, RTL is significantly lower than that of women with a preserved reproductive function, P = 0.0000001. The value of RTL is significantly lower in women with ERL under 35 years compared with control, P = 0.0000001, and is similar to value of RTL in women in the control group at the age of 36, P&gt; 0.05. Conclusions. The telomere lengths is significantly lower in both older women and women with ERL. The similarity of RTLvalue in women with ERL up to 35 years of age and in women with a preserved reproductive function at the age of 36 years testifies to the telomeric theory of reproductive aging. Keywords: telomeres, RT-PCR, women, age, early reproductive loss.

Telomere length in peripheral blood leukocytes and risk of renal cell carcinoma.

BackgroundTelomeres are essential for chromosomal stability and may play a key role in carcinogenesis. Telomere length is suggested as a tentative biomarker of risk for renal cell carcinoma (RCC). However, results of previous association studies between telomere length and risk for RCC are inconsistent.MethodsWe evaluated RCC risk in relation to peripheral blood leukocyte telomere length using a hospital-based case–control study of 169 RCC cases and 189 controls. Cases were histologically-confirmed RCC patients who were treated at the Moffitt Cancer Center (Tampa, FL). Controls with no history of cancer underwent a screening exam at the Lifetime Cancer Screening Center at Moffitt Cancer Center to rule out the presence of cancer. Relative telomere length (RTL) was measured by quantitative real-time polymerase chain reaction (PCR) using peripheral blood leukocyte DNA. Logistic regression was used to determine the association between RTL and RCC risk.ResultsAs expected, increasing age was inversely correlated with RTL (Pearson r=−0.213, P=0.003) among controls but not cases. Average RTL was significantly shorter in cases as compared with controls [mean ± standard deviation (SD): 3.18±1.50 and 4.39±1.99, respectively, P<0.001]. In contrast, average RTL was not significantly different by gender, race, smoking status among controls or by clinical stages among RCC cases. In regression analysis, we observed that shorter RTL is significantly associated with RCC risk [odds ratio (OR) =1.48; 95% confidence interval (CI): 1.27–1.71] after adjustment for covariates.ConclusionsWe found that shorter RTL is associated with an increased risk for RCC. Our findings suggest that telomere length may be involved in the development of RCC.

The aging lung: tissue telomere shortening in health and disease

BackgroundTelomere shortening has been associated with several lung diseases. However, telomere length is generally measured in peripheral blood leucocytes rather than in lung tissue, where disease occurs. Consequently, telomere dynamics have not been established for the normal human lung nor for diseased lung tissue. We hypothesized an age- and disease-dependent shortening of lung tissue telomeres.MethodsAt time of (re-)transplantation or autopsy, 70 explant lungs were collected: from unused donors (normal, n = 13) and patients with cystic fibrosis (CF, n = 12), chronic obstructive pulmonary disease (COPD, n = 11), chronic hypersensitivity pneumonitis (cHP, n = 9), bronchiolitis obliterans syndrome (BOS) after prior transplantation (n = 11) and restrictive allograft syndrome (RAS) after prior transplantation (n = 14). Lungs were inflated, frozen and then scanned using CT. Four tissue cores from distinct lung regions were sampled for analysis. Disease severity was evaluated using CT and micro CT imaging. DNA was extracted from the samples and average relative telomere length (RTL) was determined using real-time qPCR.ResultsThe normal lungs showed a decrease in RTL with age (p < 0.0001). Of the diseased lungs, only BOS and RAS showed significant RTL decrease with increasing lung age (p = 0.0220 and p = 0.0272 respectively). Furthermore, we found that RTL showed considerable variability between samples within both normal and diseased lungs. cHP, BOS and RAS lungs had significant shorter RTL in comparison with normal lungs, after adjustment for lung age, sex and BMI (p < 0.0001, p = 0.0051 and p = 0.0301 respectively). When investigating the relation between RTL and regional disease severity in CF, cHP and RAS, no association was found.ConclusionThese results show a progressive decline in telomere length with age in normal, BOS and RAS lungs. cHP, BOS and RAS lungs demonstrated shorter RTL compared to normal lungs. Lung tissue RTL does not associate with regional disease severity within the lung. Therefore, tissue RTL does not seem to fully reflect peripheral blood telomere length.

Application of the psychological aging scale for healthy people: A preliminary study based on empirical research

To explore the distribution of psychological aging in healthy population and its relationship with telomere length in peripheral blood leukocyte, and to provide reference for aging evaluation. Methods: Stratified random samples were obtained according to age and they were divided into 9 age groups. The age-related psychological information were collected from healthy people by using the self-made scale. Situation of psychological aging, correlation between age and telomere length and score of this scale were analyzed by statistical software. Results: A total of 2 100 questionnaires were distributed, and 2 060 of them were valid and has been recovered, with an efficiency of 98.10%. The ratio of male to female was 0.95:1; psychological aging score was in the range of 8.62-23.14; cognitive function score was in the range of 2.25-10.77; emotion score was in the range of 1.45-6.73; personality score was in the range of 0.96-4.22; motivation score was in the range of 1.50-7.18. The correlation coefficient of psychological aging scores with age was 0.721 (P<0.001). The average relative telomere length was 1.06±0.26, and relative telomere length in different age groups were significantly different (F=35.803, P<0.001). Telomere length was negatively correlated with age (r=-0.964, P<0.001) and psychological aging scores (r=-0.915, P=0.004). Conclusion: The empirical study of physiological aging scale in healthy population shows that the scores of physical aging are increased with age and that the telomere length is negatively correlated with aging scores, suggesting that the scale can provide reference for the comprehensive evaluation of aging.

Analytical Validation of Relative Average Telomere Length Measurement in a Clinical Laboratory Environment.

Average telomere length in whole blood has become a biomarker of aging, disease, and mortality risk across a broad range of clinical conditions. The most common method of telomere length measurement for large patient sample sets is based on quantitative PCR (qPCR). For laboratory-developed tests to be performed on clinical samples, they must undergo a rigorous analytical validation, currently regulated under CLIA. Whole blood samples from 40 donors were used in the analytical validation of methods for relative average telomere length (rATL) measurement. Three technical replicate DNA samples were extracted from each whole blood sample and placed in three independent wells on a sample plate. Each of these sample plates was assayed 12 times during the validation process. The study was conducted over a 20-day period, once in the morning and once in the evening, using 3 different operators. Our process of rATL measurement beginning with DNA extraction followed by qPCR-based assay resulted in repeatability and reproducibility CV of <5% and amplification efficiencies near 100%. The validated assay was used to establish a reference interval derived from 2 cohorts of individuals: (a) San Francisco Bay area (n = 504) and (b) a US cross-sectional, demographic population (n = 357). We present advances in the establishment of a highly reproducible analytically validated process for determining rATLs in a CLIA laboratory environment.

Analytical Validation of a Relative Average Telomere Length Assay in a Donor Population for Hematopoietic Stem Cell Transplant (HCT)

Analytical Validation of a Relative Average Telomere Length Assay in a Donor Population for Hematopoietic Stem Cell Transplant (HCT)

Shortened Telomeres in Families With a Propensity to Autism

Shortened telomeres have been linked to poorer health outcomes. Exposure to psychological stress is associated with accelerated telomere shortening, and a well-established body of evidence indicates that families with a child with autism spectrum disorder (ASD) experience heightened levels of psychological stress. Also, alterations in a number of biological processes implicated in telomere length dynamics (i.e., oxidative stress, DNA methylation) have been linked to ASD susceptibility. We examined whether families of children with ASD who have an infant show shortened telomeres. Saliva samples were collected from infants, their older sibling (proband), and parents in families with or without a child with ASD. Infants and their families were designated as high-risk for ASD (HRA; n= 86) or low-risk for ASD (LRA; n= 118) according to the older siblings' diagnostic status. We used the real-time polymerase chain reaction (PCR) telomere assay to determine relative average telomere length for each participant. HRA families demonstrated significantly shorter telomere length relative to LRA families. This effect was observed at the individual family member level, with infants, probands, and mothers in HRA families showing reduced relative telomere length compared to individuals in LRA families; although not significant, fathers of high-risk infants showed a similar pattern of decreased telomere length. Families of children with ASD who have an infant show shortened telomeres relative to families with no history of ASD. These results suggest that such "high-risk" families should be monitored for the physical and mental health consequences that are often associated with accelerated telomere shortening.

Telomere shortening in Down syndrome patients--when does it start?

Down syndrome (DS) is one of the most common aneuploidy. In general population, its prevalence is 1:600-1:800 live births. It is caused by a trisomy of chromosome 21. DS is phenotypically manifested by premature aging, upward slant to the eyes, epicanthus, flattened face, and poor muscle tone. In addition to physical changes, this syndrome is characterized by early onset of diseases specific to old age, such as Alzheimer's disease, vision and hearing problems, and precocious menopause. Since DS symptoms include premature aging, the shortening of telomeres might be one of the markers of cellular aging. Consequently, the aim of the study was to determine the length of the telomeres in leukocytes from the blood of juvenile patients with DS (n=68) compared to an age-matched control group (n=56) and also to determine the diagnostic or predictive value for this parameter. We show that, for the first time, in juveniles, the average relative telomere length in studied subjects is significantly longer than in the control group (50.46 vs. 40.56, respectively arbitrary units [AU]; p=0.0026). The results provide interesting basis for further research to determine the causes and consequences of telomere maintaining and the dynamics of this process in patients with DS.

Telomere length in non-neoplastic gastric mucosa and its relationship to H. pylori infection, degree of gastritis, and NSAID use.

Telomere shortening occurs with human aging in many organs and tissues and is accelerated by rapid cell turnover and oxidative injury. We measured average telomere length using quantitative real-time PCR in non-neoplastic gastric mucosa and assessed its relationship to H. pylori-related gastritis, DNA methylation, ulcer disease, and nonsteroidal anti-inflammatory drug (NSAID) usage. Gastric biopsies were obtained from 151 cancer-free subjects including 49 chronic NSAID users and 102 nonusers. Relative telomere length in genomic DNA was measured by real-time PCR. H. pylori infection status, histological severity of gastritis, and serum pepsinogens (PGs) were also investigated. E-cadherin (CDH1) methylation status was determined by methylation-specific PCR (MSP). Average relative telomere length of H. pylori-infected subjects was significantly shortened when compared to H. pylori-negative subjects (p = 0.002) and was closely associated with all histological parameter of gastritis (all p values <0.01) and CDH1 methylation (p = 0.0002). In H. pylori-negative subjects, NSAID users presented significantly shorter telomere length than nonusers (p = 0.028). Shorter telomere length was observed in duodenal and gastric ulcer patients compared with non-ulcer subjects among NSAID users. Telomere shortening is closely associated with severity of H. pylori-induced gastritis and CDH1 methylation status. Also, telomere shortening is accelerated by NSAID usage especially in H. pylori-negative subjects.

Leukocyte telomere length and hemostatic factors in a South African cohort: the SABPA Study

Incident atherothrombotic disease is predicted by leukocyte telomere length, a marker of biological age, and hemostatic factor levels, indicating a hypercoagulable state. We hypothesized that shorter telomeres are associated with elevated circulating levels of hemostatic factors. We examined 171 South African (black) and 182 Caucasian (white) schoolteachers (mean age ± standard deviation, 48.5 ± 9.0 years; 50.4% women). Levels of fibrinogen, von Willebrand factor antigen (VWF:Ag), D-dimer and plasminogen activator inhibitor-1 antigen (PAI-1:Ag) were measured in plasma, and values were log-transformed before analysis. Relative average telomere length (content of telomere PCR product/content of human β-globin PCR product ratio, i.e. telomere/single-copy gene ratio) was assessed with multiplex quantitative real-time PCRs. Multivariate analyses included demographics, metabolic factors, health behavior, and medication. Africans had shorter mean telomere length (0.82, 95% confidence interval [CI] 0.79-0.86 vs. 1.07, 95% CI 1.04-1.10) and higher fibrinogen (B = 0.085, 95% CI 0.061-0.109) and PAI-1:Ag (B = 0.255, 95% CI 0.206-0.303) levels, but lower VWF:Ag levels (B = - 0.059, 95% CI - 0.089 to - 0.028), than Caucasians. Shorter telomeres were associated with higher fibrinogen (B = - 0.045, 95% CI - 0.088 to - 0.001), VWF:Ag (B = - 0.137, 95% CI - 0.193 to - 0.081) and D-dimer (B = - 0.201, 95% CI - 0.377 to - 0.025) levels, conditional on ethnicity. An interaction emerged between ethnicity and telomere length for VWF:Ag level; that is, shorter telomeres were associated with higher VWF:Ag levels in Caucasians (B = - 0.170, 95% CI - 0.232 to - 0.108) but not in Africans. Shorter telomeres were associated with increased levels of several hemostatic factors after adjustment for confounding variables, whereby ethnicity partially moderated this effect. A relationship between accelerated biological aging and hypercoagulability might contribute to the risk of premature atherothrombotic events.

Telomere length in non-neoplastic colonic mucosa in ulcerative colitis (UC) and its relationship to the severe clinical phenotypes.

Telomere shortening occurs with human aging in many organs and tissues and is accelerated by rapid cell turnover and oxidative injury. To clarify the clinical importance of telomere shortening in colonic mucosa in ulcerative colitis (UC), we measured average telomere length using quantitative real-time PCR in non-neoplastic colonic mucosa in UC patients and assessed its relationship to various clinical subtypes. Relative telomere length in genomic DNA was measured in colonic biopsies obtained from rectal inflammatory mucosa from 86 UC patients as well as paired non-inflammatory proximal colonic mucosae from 10 patients. Data were correlated with various clinical phenotypes. In paired samples, average relative telomere length of rectal inflammatory mucosa was shortened compared to normal appearing proximal colon in eight out of ten cases (p=0.01). Telomere length shortening was significantly associated with more severe Mayo endoscopic subscore (p<0.0001) and cases needing surgery due to toxic megacolon or cancer occurrence (p=0.043). When the severe clinical phenotype was defined as having at least one of following phenotypes, more than two times of hospitalization, highest Mayo endoscopic subscore, steroid dependent, refractory, or needing operation, average relative telomere length was significantly shortened in the same phenotypes than the others (p=0.003). Telomere shortening is associated with more severe clinical phenotypes of UC, reflecting severe inflammatory state in the colonic mucosa.

Seasonal variation in telomere length of a hibernating rodent

Small hibernating rodents have greater maximum lifespans and hence appear to age more slowly than similar-sized non-hibernators. We tested for a direct effect of hibernation on somatic maintenance and ageing by measuring seasonal changes in relative telomere length (RTL) in the edible dormouse Glis glis. Average RTL in our population did not change significantly over the hibernation season, and a regression model explaining individual variation in post-hibernation RTL suggested a significant negative effect of the reduction in body mass over the inactive hibernation period (an index of time spent euthermic), supporting the idea that torpor slows ageing. Over the active season, RTL on average decreased in sub-adults but increased in adults, supporting previous findings of greater telomere shortening at younger ages. Telomere length increase might also have been associated with reproduction, which occurred only in adults. Our study reveals how seasonal changes in physiological state influence the progress of life-history traits, such as somatic maintenance and ageing, in a small hibernating rodent.

Telomere length and LINE1 methylation is associated with chromosomal aberrations in peripheral blood

The frequency of chromosomal aberrations in peripheral blood predicts a probable cancer risk. The individual telomere length and methylation of repetitive elements may be susceptibility factors for chromosomal aberrations. A cohort of healthy Norwegian men (N = 364) recruited during 1980-1999 were analyzed for chromosomal aberrations in phytohemagglutinin-stimulated lymphocytes from peripheral blood. Chromosome-type or chromatid-type aberrations were scored. DNA was extracted from slides cytogenetically analyzed and relative average telomere length and methylation of LINE1 repeats were determined by quantitative polymerase chain reaction and bisulfite pyrosequencing, respectively. Information about individuals with malignant tumors (N = 49) diagnosed after chromosomal aberrations testing until end of 2008 was obtained and two matched controls per case were used in a nested case-control analysis. Shorter relative telomere length and higher methylation of LINE1 were associated with higher frequency of total chromosomal aberrations (β = -0.76, P = 0.022; and β = 0.042, P = 0.048, respectively; age-adjusted ordinal regression). The telomere length was stronger associated with chromosome-type (β = -1.00, P = 0.006) than with chromatid-type aberrations (β = -0.49, P = 0.115). The LINE1 methylation was stronger associated with chromatid-type (β = 0.062, P = 0.003) than with chromosome-type aberrations (β = 0.018, P = 0.41). Telomere length [individuals with short telomeres odds ratio (OR) = 0.87, 95% confidence interval (CI) 0.38-2.0], LINE1 (individuals with high methylation OR = 1.04, 95% CI 0.43-2.5) and chromosomal aberrations (individuals with high frequency OR = 1.6, 95% CI 0.63-3.9) at baseline did not predict cancer risk, but the conclusions were hampered by low statistical precision. The results suggest that shorter telomere length and higher LINE1 methylation in peripheral blood lymphocytes are predisposition factors for increased frequency of chromosomal aberrations.

Telomere Length Is An Independent Predictor of Outcome After Therapy in CLL: Results From the UKCLL4 Trial,

Abstract 3884▪▪This icon denotes a clinically relevant abstractTelomere length measurement has been reported to predict time to first treatment (TTFT) and overall survival from diagnosis in chronic lymphocytic leukaemia (CLL). Of note, the study by Rossi et al (Leukemia, 2009), of presentation samples from over 400 CLL patients, showed short telomere length predicted reduced TTFT, independent of established prognostic biomarkers such as disease stage, immunoglobulin heavy chain variable region (IGHV) mutation status and unfavourable genomic aberrations. However, to date no studies have been reported on the value of telomere length as a biomarker in CLL at time of first therapy.We have used the monochrome multiplex quantitative PCR (MMQPCR) method of Cawthon (Nucleic Acids Research, 2009), to determine relative average telomere length in peripheral blood mononuclear cell DNA from treatment naive CLL patients at time of enrolment into the phase III UKCLL4 trial. MMQPCR reports a telomere length value (T/S) which has been shown to correlate linearly with mean telomere terminal restriction fragment length as determined by southern blotting. Telomere length was measured for 375/777 patients selected from the trial, of the 375 cases 157, 85 and 133 were randomised to the Chlorambucil, Fludarabine or Fludarabine plus Cyclophosphamide (FC) arms respectively. Other than an increased proportion of cases from FC arm, the selected cohort did not differ from the whole trial cohort.The median T/S for all cases was 2.60 (range, 0.61–19.05). In a multiple linear regression model, only age at trial entry and IGHV homology to germline had significant predictive effect for T/S (p=0.023 and <0.0001 respectively). Whereas, Beta-2 microglobulin levels (B2M), WBC, time from diagnosis to study entry, percentage ZAP70 positive tumour cells and percentage CD38 positive tumour cells did not. T/S was significantly lower in cases with unmutated compared with mutated IGHV genes, with del 17p compared with no del 17p and with del 11q compared with no del 11q (all p<0.001) but did not significantly differ with disease stage, gender, or between those cases with or without trisomy 12.Splitting cases into two groups based on those with T/S above or below the median, short telomeres were associated with TP53 loss or mutation, del 11q and unmutated IGHV (all p<0.001) but not with gender or disease stage. Cases with short telomeres also showed significantly higher expression of ZAP70 and CD38 (both p<0.001) and of B2M (p=0.03).In univariate survival analysis, cases with short telomeres showed significantly reduced progression free survival after therapy (PFS) (median; 21.1 months v 33.3 months, p<0.001) and overall survival after therapy (OS) (median; 57.5 months v 108.7 months, p<0.001). Stratifying by IGHV mutational status; short telomeres remained associated with significantly reduced PFS and OS in both IGHV mutated cases (PFS, median; 22.1 months v 42.3 months, p=0.002 and OS, median; 75.9 months v not reached, p<0.001) and IGHV unmutated cases (PFS, median; 21.7 months v 25.7 months, p=0.049 and OS, median; 54.8 months v 81.9 months, p=0.005).Multivariate survival analysis, selected short telomere length as an independent predictor of reduced PFS (Hazard ratio (HR) 1.5; 95% CI 1.1–2.0; p=0.011) and OS (HR 1.9; 95% CI 1.3–2.8; p=0.002) in a model containing treatment arm, IGHV mutational status, age, gender, disease stage, del17p, del11q, ZAP70 expression and CD38 expression (Table 1).Table 1 –Multivariate Analysis for PFS and OS in a 236 Patient Cohort from UKCLL4 Trial.OutcomeCovariateHazard Ratio (HR)95% CI for HRSignificance (p)PFSShort telomeres1.501.10–2.050.011Treatment with FC0.360.26–0.49<0.001IGHV unmutated1.731.28–2.35<0.001Deletion 17p6.513.56–11.92<0.001Deletion 11q1.521.08–2.150.017OSShort telomeres1.881.27–2.780.002IGHV unmutated2.441.58–3.77<0.001Age1.051.03–1.07<0.001Deletion 17p6.843.63–12.89<0.001Only covariates selected as significant are listed above.These results demonstrate that telomere length is a powerful independent predictor of outcome after alkylating agent/purine analogue therapy in CLL. The simplicity and low cost of the MMQPCR assay for telomere length measurement warrants validation of these findings and comparison with other assays for telomere length in other large clinical trials. If confirmed, this prognostic biomarker has the potential for more widespread use in CLL. Disclosures:Gonzalez de Castro:The Institute of Cancer Research: Employment.

Telomere length and early severe social deprivation: linking early adversity and cellular aging.

Accelerated telomere length attrition has been associated with psychological stress and early adversity in adults; however, no studies have examined whether telomere length in childhood is associated with early experiences. The Bucharest Early Intervention Project is a unique randomized controlled trial of foster care placement compared with continued care in institutions. As a result of the study design, participants were exposed to a quantified range of time in institutional care, and represented an ideal population in which to examine the association between a specific early adversity, institutional care and telomere length. We examined the association between average relative telomere length, telomere repeat copy number to single gene copy number (T/S) ratio and exposure to institutional care quantified as the percent of time at baseline (mean age 22 months) and at 54 months of age that each child lived in the institution. A significant negative correlation between T/S ratio and percentage of time was observed. Children with greater exposure to institutional care had significantly shorter relative telomere length in middle childhood. Gender modified this main effect. The percentage of time in institutional care at baseline significantly predicted telomere length in females, whereas the percentage of institutional care at 54 months was strongly predictive of telomere length in males. This is the first study to demonstrate an association between telomere length and institutionalization, the first study to find an association between adversity and telomere length in children, and contributes to the growing literature linking telomere length and early adversity.

Age-Related Telomere Shortening Occurs in Lens Epithelium from Old Rats and is Slowed by Caloric Restriction

We have investigated whether the average relative telomere length of lens epithelial cells (LECs) from brown Norway rats decreases with the age of the donor animal, and whether chronic caloric restriction (CR) of the rats delays the telomere shortening. Our previous studies have demonstrated that clonal proliferative potential of rodent LECs as well as the in vivo rate of DNA synthesis decreases with age and that this decrease is slowed by chronic lifelong caloric restriction (CR). In order to determine if telomeric shortening might be involved in this loss of proliferative potential, we examined relative telomeric lengths in young, old ad lib fed (AL), and old calorically restricted (CR) brown Norway rats. We used fluorescence in situ hybridization with a peptide nucleic acid probe (PNA) complementary to the telomeric repeat sequence to quantitate relative telomere lengths in LECs in lens sections (TELO-FISH). Control experiments demonstrated that the PNA probe binding was restricted almost entirely to the terminal portions of the rat chromosomes with less than 5% bound at interstitial sites in typical metaphase spreads. The relative telomere lengths of interphase human fibroblast standards, as determined by TELO-FISH, were in good agreement with terminal restriction fragment analyses of the same standards and with literature values for rat cells. The average telomere lengths of interphase nuclei in the old AL rat LECs were found to be 21% shorter than paired young AL controls (P<0.01 by Wilcoxian signed rank test). The calorically restricted old rats had less telomere erosion (12%) than the old AL group (P<0.05). Although it is not clear whether such moderate telomeric erosion can limit cell division in rodent LECs, the telomeric shortening correlated well with previous studies demonstrating reduced clonal, replicative potential, and reduced rates of in vivo DNA replication in LECs from old rodents and a delay in this attenuation in animals on chronic CR.