Telomere length analysis in monocytes and lymphocytes from patients with systemic lupus erythematosus using multi-color flow-FISH

In order to analyse telomere length in subsets of human peripheral blood lymphocytes and monocytes, we modified a recently developed multicolor flow- fluorescent in situ hybridization (FISH) methodology that combines flow-FISH and antibody staining for cell surface antigens. We analysed telomere length of peripheral blood mononuclear cells in a group of 22 patients with systemic lupus erythematosus (SLE) and 20 age-matched healthy donors. We found that neither CD4+, CD8+, CD19+ cells nor CD14+ monocytes have significantly shorter telomeres compared with their healthy counterparts. On the basis of these findings, we then used monocyte telomere length as internal reference in order to control for intra-individual variability in telomere length. By using this approach, we could demonstrate significant telomere shortening in all three lymphocyte subsets (in all cases P < 0.05) compared with monocytes. However, these differences did not vary significantly between SLE patients and controls. In summary, telomere lengths in subpopulations of hematopoietic cells can be monitored in patients with SLE using multicolor flow-FISH. While confirming data by other groups on telomere length in lymphocyte subpopulations, our data argue against an increased proliferation rate of peripheral blood monocytes reflected by accelerated telomere shortening in patients with SLE.     

Telomere length shortening in chronic myelogenous leukemia is associated with reduced time to accelerated phase

Telomere shortening is associated with disease evolution in chronic myelogenous leukemia (CML). We have examined the relationship between diagnostic telomere length and outcome in 59 patients with CML who entered into the MRC CMLIII Trial by Southern blot hybridization using the (TTAGGG)(4) probe. Age-adjusted telomere repeat array (TRA) reduction was found to significantly correlate with time from diagnosis to acceleration, such that patients with a larger TRA reduction entered the accelerated phase more rapidly (r = -0.50; P =.008). Cox-regression analysis for this group was suggestive of a relationship between a greater TRA-reduction and a shorter time to acceleration (P =.054). Age-adjusted TRA reduction did not significantly affect either the time to blast crisis or overall survival. Our results show that telomere shortening observed at the time of diagnosis in CML significantly influences the time to progress to the accelerated phase. The measurement of diagnostic TRA may prove to be clinically important in the selection of patients at high risk of disease transformation in CML.     

Telomere length is reduced in 9- to 16-year-old girls exposed to gestational diabetes in utero

Aims/hypothesis

Shortened telomere length is a marker of cell damage and is associated with oxidative stress, chronic inflammation and metabolic disease. We hypothesised that the offspring of women with gestational diabetes mellitus (GDM) with increased risk of cardiovascular and metabolic diseases might exhibit shorter telomere length.

Methods

We investigated telomere length in 439 GDM and 469 control group offspring, aged between 9 and 16 years, recruited from the Danish National Birth Cohort. Relative telomere length was measured in peripheral blood DNA (n?=?908) using a quantitative PCR approach. Multivariate regression analysis was used to investigate the association between mothers’ GDM status and telomere length in the offspring.

Results

Female offspring had longer telomeres than males. Offspring of mothers with GDM had significantly shorter telomere length than control offspring, but this difference was observed only in girls. There was a negative association between telomere length and GDM exposure among the female offspring (14% shorter telomeres, p?=?0.003) following adjustment for the age of the offspring. Telomere length in female offspring was negatively associated with fasting insulin levels and HOMA-IR (p?=?0.03). Maternal age, smoking, gestational age, birthweight and the offspring’s anthropometric characteristics were not associated with telomere length (p?≥?0.1).

Conclusions/interpretation

The 9- to 16-year-old girls of mothers with GDM had shorter telomeres than those from the control population. Further studies are needed to understand the extent to which shortened telomere length predicts and/or contributes to the increased risk of disease later in life among the offspring of women with GDM.

     

Telomere length of circulating leukocytes is decreased in patients with chronic heart failure.

OBJECTIVES: This study sought to test the hypothesis that patients with chronic heart failure (CHF) have shorter telomeres compared with age-balanced and gender-balanced healthy individuals. BACKGROUND: Telomere length is considered to be a marker of biological aging. Chronic heart failure might be viewed as a condition associated with accelerated biological aging. METHODS: The telomere length ratio of leukocytes was determined prospectively by a quantitative polymerase chain reaction-based method in a case-control setting involving 803 participants: 183 healthy individuals and 620 CHF patients, ages 40 to 80 years, New York Heart Association functional class II to IV, and left ventricular ejection fraction of 0.40 or less. RESULTS: The median telomere length ratio was 0.64 (interquartile range [IQR] 0.47 to 0.88) in CHF patients compared with 1.05 (IQR 0.86 to 1.29) in control patients (p < 0.001). The telomere length ratio in CHF patients related to severity of disease (median value [IQR] of patients with New York Heart Association class II, III, or IV function was 0.67 [0.48 to 0.92], 0.63 [0.46 to 0.86], and 0.55 [0.46 to 0.75], respectively; p for trend <0.05). In addition, telomeres were shorter in patients with an ischemic compared with a nonischemic etiology of CHF. Patients with none, 1 (coronary, cerebral, or peripheral vascular disease), 2 (any combination of the previous), or 3 atherosclerotic manifestations had a median (IQR) telomere length of 0.72 (0.51 to 1.01), 0.65 (0.48 to 0.87), 0.48 (0.39 to 0.72), and 0.43 (0.27 to 0.67), respectively (p for trend <0.001). CONCLUSIONS: Telomere length is shorter in patients with CHF compared with age-balanced and gender-balanced control patients, and related to the severity of disease. In addition, telomere length was incrementally shorter according to the presence and extent of atherosclerotic disease manifestations.     

Telomere length is paternally inherited and is associated with parental lifespan

Telomere length (TL) is emerging as a biomarker for aging and survival. To evaluate factors influencing this trait, we measured TL in a large homogeneous population, estimated the heritability (h(2)), and tested for parental effects on TL variation. Our sample included 356 men and 551 women, aged 18-92 years, from large Amish families. Mean TL in leukocytes was measured by quantitative PCR (mean: 6,198 +/- 1,696 bp). The h(2) of TL was 0.44 +/- 0.06 (P < 0.001), after adjusting for age, sex, and TL assay batch. As expected, TL was negatively correlated with age (r = -0.40; P < 0.001). There was no significant difference in TL between men and women, consistent with our previous findings that Amish men lived as long as Amish women. There was a stronger and positive correlation and association between TL in the offspring and paternal TL (r = 0.46, P < 0.001; beta = 0.22, P = 0.006) than offspring and maternal TL (r = 0.18, P = 0.04; beta = -0.02, P = 0.4). Furthermore, we observed a positive correlation and association between daughter's TL and paternal lifespan (r = 0.20, P < 0.001; beta = 0.21, P = 0.04), but not between daughter's TL and maternal lifespan (r = -0.01, beta = 0.04; both P = not significant). Our data, which are based on one of the largest family studies of human TL, support a link between TL and aging and lifespan and suggest a strong genetic influence, possibly via an imprinting mechanism, on TL regulation.     

Telomere length changes in patients with aplastic anaemia

To investigate telomere changes in patients with aplastic anaemia (AA) and clinical factors influencing the telomere dynamics, telomere length (TL) was measured in peripheral blood mononuclear cells using Southern blot analysis of 42 patients with AA and 39 healthy normal controls. Nineteen patients received supportive treatment only, while the remaining 23 patients received immunosuppressive therapy with anti-thymocyte globulin or anti-lymphocyte globulin +/- cyclosporin A. In AA patients, TL was on average 1.41 kb shorter than that of age-matched normal controls (P < 0.001). In patients treated with immunosuppression, the mean TL of non-responders was significantly shorter than that of age-matched normal controls (P < 0.001), while no difference in TL was detected in responders compared with controls. Positive correlation was observed between the extent of telomere shortening, the severity of neutropenia (P = 0.05) and the degree of mean corpuscular volume elevation (P = 0.005) at the time of the study. However, there was no correlation with time elapsed since diagnosis (P = 0.214). These findings suggest that haematopoietic stem cells in patients with AA rapidly lose TL at the onset of the disease. The TL shortening may reflect the severity of impairment of haematopoiesis.     

Telomere length is reset during early mammalian embryogenesis

The enzyme telomerase is active in germ cells and early embryonic development and is crucial for the maintenance of telomere length. Whereas the different length of telomeres in germ cells and somatic cells is well documented, information on telomere length regulation during embryogenesis is lacking. In this study, we demonstrate a telomere elongation program at the transition from morula to blastocyst in mice and cattle that establishes a specific telomere length set point during embryogenesis. We show that this process restores telomeres in cloned embryos derived from fibroblasts, regardless of the telomere length of donor nuclei, and that telomere elongation at this stage of embryogenesis is telomerase-dependent because it is abrogated in telomerase-deficient mice. These data demonstrate that early mammalian embryos have a telomerase-dependent genetic program that elongates telomeres to a defined length, possibly required to ensure sufficient telomere reserves for species integrity.     

Telomere length shortening in non-Hodgkin's lymphoma patients undergoing chemotherapy

We investigated telomere length changes in patients with non-Hodgkin's lymphoma (NHL) receiving conventional-dose chemotherapy. Using Southern blot analysis, telomere length was measured in peripheral blood mononuclear cells from five NHL patients at diagnosis, 15 NHL patients after chemotherapy, and 39 healthy controls. Compared with age-matched putative normal controls, telomeres were significantly shorter in NHL patients at diagnosis. Mean telomere length was shorter after chemotherapy than before chemotherapy and was shorter after chemotherapy than in age-matched putative healthy controls. There was no correlation between the extent of telomere shortening and time elapsed after chemotherapy. These findings suggest that in NHL patients hematopoietic stem cells lose telomere length during the recovery period from bone marrow suppression after conventional-dose chemotherapy.     

Telomere length in leukocyte subpopulations of patients with aplastic anemia

In most human cells, the average length of telomere repeats at the ends of chromosomes provides indirect information about their mitotic history. To study the turnover of stem cells in patients with bone marrow failure syndromes, the telomere length in peripheral blood granulocytes and lymphocytes from patients with aplastic anemia (AA, n = 56) and hemolytic paroxysmal nocturnal hemoglobinuria (n = 6) was analyzed relative to age-matched controls by means of fluorescence in situ hybridization and flow cytometry. The telomere lengths in granulocytes from patients with AA were found to be significantly shorter than those in age-adjusted controls (P =.001). However, surprisingly, telomere length in granulocytes from AA patients who had recovered after immunosuppressive therapy did not differ significantly from controls, whereas untreated patients and nonresponders with persistent severe pancytopenia showed marked and significant telomere shortening. These results support extensive proliferation of hematopoietic stem cells in subgroups of AA patients. Because normal individuals show significant variation in telomere length, individual measurements in blood cells from AA patients may be of limited value. Whether sequential telomere length measurements can be used as a prognostic tool in this group of disorders remains to be clarified. (Blood. 2001;97:895-900)     

Telomere length in myelodysplastic syndromes

We have studied telomere length in the bone marrow cells or the granulocyte and lymphocyte cell fractions of 54 patients with myelodysplastic syndromes (MDS) by Southern blot hybridization using the (TTAGGG)₄ probe. The average telomere length expressed as the peak telomere repeat array (TRA) in the peripheral blood, or bone marrow samples obtained from a group of 21 healthy age-matched controls (26–89 years old, mean age 55), ranged between 7.5 and 9.5 kb (mean peak TRA 8.6 kb). Twenty-four patients with refractory anemia (RA) were studied; 10/24 (42%) had telomere reduction (<7.5 kb) relative to age-matched controls and the mean peak TRA was 7.5 kb (range 4.0–9.0 kb). Eleven patients with RA with excess blasts (RAEB) were studied; 5/11 (45%) had reduced telomeres relative to age-matched controls and the mean peak TRA was 7.1 kb (range 5.0–9.0 kb). Eighteen patients with MDS in transformation to AML, comprising 15 with RAEB in transformation (RAEBt) and 3 with CMML in transformation (CMMLt), were also studied. Thirteen of eighteen patients (72%) had telomere reduction relative to age-matched controls and the mean peak TRA was 6.1 kb (range 3.5–9.0 kb). Thirty-six patients included in the study had either a normal karyotype or a simple karyotype (1 karyotypic change) and 20/36 (55%) of these had telomere reduction and the mean peak TRA was 7.1 kb (range 4.3–9.0 kb); 8 patients had a complex karyotype (3 or more karyotypic changes) and 5/8 (62%) of these had telomere reduction and the mean peak TRA was 6.1 kb (range 3.5–9.0 kb). We conclude, firstly that there is heterogeneity of telomere length in MDS and that this is observed throughout the spectrum of FAB-subtypes. Secondly, these data show that a marked reduction in telomere length in MDS if often associated with leukemic transformation and with the presence of complex karyotypic abnormalities. Am. J. Hematol. 56:266–271, 1997. © 1997 Wiley-Liss, Inc.     

Telomere length inversely correlates with pulse pressure and is highly familial

There is evidence that telomeres, the ends of chromosomes, serve as clocks that pace cellular aging in vitro and in vivo. In industrialized nations, pulse pressure rises with age, and it might serve as a phenotype of biological aging of the vasculature. We therefore conducted a twin study to investigate the relation between telomere length in white blood cells and pulse pressure while simultaneously assessing the role of genetic factors in determining telomere length. We measured by Southern blot analysis the mean length of the terminal restriction fragments (TRF) in white blood cells of 49 twin pairs from the Danish Twin Register and assessed the relations of blood pressure parameters with TRF. TRF length showed an inverse relation with pulse pressure. Both TRF length and pulse pressure were highly familial. We conclude that telomere length, which is under genetic control, might play a role in mechanisms that regulate pulse pressure, including vascular aging.     

Telomere length is a critical determinant for survival in multiple myeloma

The variable clinical outcomes of Multiple Myeloma (MM) patients are incompletely defined by current prognostication tools. We examined the clinical utility of high‐resolution telomere length analysis as a prognostic marker in MM. Cohort stratification, using a previously determined length threshold for telomere dysfunction, revealed that patients with short telomeres had a significantly shorter overall survival (P < 0·0001; HR = 3·4). Multivariate modelling using forward selection identified International Staging System (ISS) stage as the most important prognostic factor, followed by age and telomere length. Importantly, each ISS prognostic subset could be further risk‐stratified according to telomere length, supporting the inclusion of this parameter as a refinement of the ISS.     

Telomere length study in celiac disease

OBJECTIVES: Telomeres are important structures that are critical for maintaining chromosomal integrity and cell surveillance. The aim of this study was to analyze telomere length in patients with celiac disease (CD), a multifactorial disorder with a strong genetic component that exhibits genomic instability and cancer predisposition, particularly T-cell lymphomas. METHODS: Telomere length measured by telomere restriction fragments (TRF) was studied in small intestinal biopsy (SIB) samples and peripheral blood lymphocytes (PBL) from 20 untreated CD patients, distributed according to the clinical form as four asymptomatic, five monosymptomatic, and 11 polysymptomatic individuals. We also analyzed TRF from normal peripheral blood lymphocytes and normal biopsy samples as normal controls. RESULTS: TRF evaluation showed a significant telomere shortening in SIB samples from CD patients (4.21 +/- 0.29 Kb) compared to PBL from the same individuals (9.17 +/- 0.35 Kb) (p < 0.0001), independently of clinical form. Mean TRF peak values from normal biopsy samples were significantly higher (8.33 +/- 0.38 Kb) than those observed in CD biopsy samples (p < 0.001). No differences between TRF values in CD-PBL and normal peripheral blood lymphocytes (8.89 +/- 0.37Kb) were found. CONCLUSIONS: Our findings in patients with CD, a disorder in which the gluten-induced mucosal injury could accelerate telomere shortening, would increase the process of end-to-end fusions resulting in chromosomal changes, supports the hypothesis that genomic instability and telomere reduction may play a role in the cancer predisposition observed in these patients.