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Aim The telomere is a structure present at the ends of chromosomes, and is known to shorten with aging and successive rounds of cell division. However, very little is known about telomere attrition in post-mitotic cells, such as neurons. Methods Using our originally developed quantitative fluorescence in situ hybridization method, we analyzed age-dependent alterations of telomere length in three types of cells in the human cerebrum: neurons and glial cells in both the gray and white matter. Results In adults, telomeres were significantly longer in neurons than in glial cells, whereas in infants, telomere lengths did not differ among the three cell types. No aging-related telomere attrition was evident in neurons. However, the telomeres of glial cells were shorter in older individuals than in younger individuals, and attrition was more rapid in the white matter than in the gray matter. Conclusions The present results suggest that the telomeres of neurons remain stable throughout life, whereas telomeres in white matter glial cells become significantly shorter with age. Examination of adults showed no significant correlation between telomere length and age in the three cell types. Although the present study was cross-sectional, the results suggest that telomere shortening before adolescence contributes to the significant decrease of telomere length in white matter glial cells. The present findings in normal cerebral tissues will be informative for future studies of telomere stability in the diseased brain. Geriatr Gerontol Int 2018; 18: 1507-1512.

Accumulated data have shown that most human somatic cells or tissues show irreversible telomere shortening with age, and that there are strong associations between telomere attrition and aging-related diseases, including cancers, diabetes and cognitive disorders. Although it has been largely accepted that telomere attrition is one of the major causes of aging-related disorders, critical aspects of telomere biology remain unresolved, especially the lack of standardized methodology for quantification of telomere length. Another frustrating issue is that no potentially promising methods for safe prevention of telomere erosion, or for telomere elongation, have been devised. Here, we review several methods for quantification of telomere length currently utilized worldwide, considering their advantages and drawbacks. We also summarize the results of our recent studies of human cells and tissues, mainly using quantitative fluorescence in situ hybridization and Southern blotting, including those derived from patients with progeria-prone Werner syndrome and trisomy 21, and several strains of induced pluripotent stem cells. We discuss the possible merits of using telomere shortness as an indicator, or a new marker, for diagnosis of precancerous states and aging-related disorders. In addition, we describe newly found factors that are thought to impact telomere dynamics, providing a new avenue for examining the unsolved issues related to telomere restoration and maintenance.

Telomere shortening occurs when cells divide, both in vitro and in vivo. On the other hand, telomerase is able to maintain telomere length in cells by adding TTAGGG repeats to the ends of telomeres. However, the interrelationships existing among telomere length, telomerase activity and growth in vertebrates remain to be clarified. In the present study we measured telomere length (terminal restriction fragment length), telomerase activity and body growth of Oryzias latipes from the embryo stage until senescence. During the rapid growth stage (age 0-7 months), telomeres shortened in parallel with decreasing telomerase activity. Then, during adolescence (age 7 months - 1 year), telomeres lengthened quickly as growth slowed and telomerase activity increased. In the adult stage (age 1-4 years) characterized by little growth, telomerase activity decreased gradually and telomeres shortened. Our data indicate that telomere attrition and restoration are linked to growth and telomerase activity, and suggest that critical loss of telomere homeostasis is associated with mortality in this animal.

The telomere is a structure present at the ends of chromosomes, and is known to shorten with aging and successive rounds of cell division. However, very little is known about telomere attrition in post-mitotic cells, such as neurons.Using our originally developed quantitative fluorescence in situ hybridization method, we analyzed age-dependent alterations of telomere length in three types of cells in the human cerebrum: neurons and glial cells in both the gray and white matter.In adults, telomeres were significantly longer in neurons than in glial cells, whereas in infants, telomere lengths did not differ among the three cell types. No aging-related telomere attrition was evident in neurons. However, the telomeres of glial cells were shorter in older individuals than in younger individuals, and attrition was more rapid in the white matter than in the gray matter.The present results suggest that the telomeres of neurons remain stable throughout life, whereas telomeres in white matter glial cells become significantly shorter with age. Examination of adults showed no significant correlation between telomere length and age in the three cell types. Although the present study was cross-sectional, the results suggest that telomere shortening before adolescence contributes to the significant decrease of telomere length in white matter glial cells. The present findings in normal cerebral tissues will be informative for future studies of telomere stability in the diseased brain. Geriatr Gerontol Int 2018; 18: 1507-1512.

In order to investigate the population dynamics of telomere status, we measured the telomere lengths of glandular cells in the adenohypophysis (AH) and pituicytes, a type of glial cell, in the neurohypophysis (NH) of 128 autopsied humans (65 men, 63 women, 0 and 102 years) using our original quantitative fluorescence in situ hybridization (Q-FISH) method. Telomeres in the AH shortened with aging in both men and women, but those of pituicytes did not. Pituicyte telomeres were significantly longer in women than in men. The data suggest that telomeres shorten with age in the AH, whereas those in pituicytes maintain a constant length throughout life. Comparison of pituicyte telomere lengths among 5 generations,18, 18-69, 70-79, 80-89, and90 years, revealed a tendency for telomeres to be longer in individuals in their 80 s and 90 s than in those in their 70 s. These findings lend support to the widely held notion that humans with longer telomeres may have a longer life span, and shed light on the biology of pituitary gland in terms of telomere length dynamics, as well contributing to the development of bioengineered hormone-producing cell replacement strategies and regenerative therapies.

Although accelerated β-cell telomere shortening may be associated with diabetes that shows a dramatically increased incidence with aging, β-cell telomere length in diabetes has never been explored.The objective of the present study was to examine telomere length in the β-cells of patients with diabetes.We determined telomere length in β- and α-cells of pancreases obtained at autopsy from 47 patients with type 2 diabetes and 51 controls, all older than 60 years.The normalized telomere to centromere ratio (NTCR), an index of telomere length, was determined for β- (NTCRβ) and α- (NTCRα) cells by quantitative fluorescence in situ hybridization.The NTCRβ was reduced by 27% ± 25% and NTCRα by 15% ± 27% in the patients with diabetes relative to the controls (P.01 for both). Importantly, the degree of shortening was significantly (P.01) greater in β-cells than in α-cells. The histogram of NTCR distribution was significantly skewed to the left in the patients with diabetes relative to the controls for both β- and α-cells, indicating preferential depletion of longer-telomere islet cells. Glycated hemoglobin was negatively correlated with β-cell telomere length, and the telomeres were significantly shorter in patients who had used hypoglycemic agents than in those who had not.The telomeres of β-cells are shortened in patients with type 2 diabetes. There may be a vicious cycle involving β-cell telomere attrition and sustained hyperglycemia.

Purpose Evaluation of the relationships existing among 3 histologic types of urothelial tumors, chromosomal instability, and telomere length. Patients and methods We examined 37 consecutive cases of papillary urothelial neoplasm, from which 26 (70.3%) were suitable for karyotype analysis, comprising 7 papillary urothelial neoplasms of low malignant potential (PUNLMPs), 10 low-grade papillary urothelial carcinomas (PUCs), and 9 high-grade PUCs. We performed karyotype and anaphase bridge analyses, and measured telomere lengths by quantitative fluorescence in situ hybridization. Results PUNLMPs were always diploid and had anaphase bridges. Low-grade PUCs showed diploidy ( n = 2), hypoploidy ( n = 4) and polyploidy ( n = 4), and high-grade PUCs showed diploidy ( n = 1) and polyploidy ( n = 8); both had anaphase bridges. The incidence of anaphase bridges did not differ significantly between PUNLMPs and high-grade PUCs ( P = 0.105). The telomere lengths of PUNLMP, low-grade PUC, and high-grade PUC, expressed as mean telomere fluorescence units (TFU)±SD, were 7906±3197, 4893±1567, and 3299±1406, respectively. The differences among the 3 groups were significant. However, 42.9% of the PUNLMPs had shorter telomeres than the mean value for low-grade PUCs, and 30.0% of the low-grade PUCs had shorter telomeres than those for high-grade PUCs. There was an inverse correlation between telomere length and the incidence of anaphase bridges. Conclusions PUNLMP appears to progress to low-grade PUC and high-grade PUC in association with telomere shortening and chromosomal instability. Our data suggest that critically shortened telomeres cause chromosomal instability during progression of papillary urothelial neoplasms.

Telomeres are nucleoprotein complexes located at the ends of eukaryotic chromosomes and are shorten with aging or various causes. Shortened telomere plays an important role for chromosomal instability in carcinogenesis, or a number of diseases in relation to aging. FISH using peptide-nucleic acid (PNA) probe is suitable for analyzing telomeres, because telomere is a part of DNA molecule and localized in chromosomal end in loop shape structure (T-loop). We introduce our telomere analysis for tissue sections and cultured cells in this paper. On the tissue sections, we analyze telomere length with telomere intensity to centromere intensity ratio (TCR), centromere as an inner control. In the cultured cells, we analyze telomere lengths on each chromosome with karyotyping. Those Q-FISH methods by PNA probe are an accurate and reliable tool for research on telomere lengths in various conditions in biology.

In the original publication of this article, Fig. 5 was published with incorrect color of the approximate lines of CBD and Control.

We have reported telomere attrition in β and α cells of the pancreas in elderly patients with type 2 diabetes, but it has not been explored how the telomere lengths of these islet cells change according to age in normal subjects. To examine the telomere lengths of β and α cells in individuals without diabetes across a wide range of ages, we conducted measurement of the telomere lengths of human pancreatic β and α cells obtained from 104 autopsied subjects without diabetes ranging in age from 0 to 100 years. As an index of telomere lengths, the normalized telomere-centromere ratio (NTCR) was determined for β (NTCRβ) and α (NTCRα) cells by quantitative fluorescence in situ hybridization (Q-FISH). We found NTCRβ and NTCRα showed almost the same levels and both decreased according to age (p

Accumulated data have shown that most human somatic cells or tissues show irreversible telomere shortening with age, and that there are strong associations between telomere attrition and aging-related diseases, including cancers, diabetes and cognitive disorders. Although it has been largely accepted that telomere attrition is one of the major causes of aging-related disorders, critical aspects of telomere biology remain unresolved, especially the lack of standardized methodology for quantification of telomere length. Another frustrating issue is that no potentially promising methods for safe prevention of telomere erosion, or for telomere elongation, have been devised. Here, we review several methods for quantification of telomere length currently utilized worldwide, considering their advantages and drawbacks. We also summarize the results of our recent studies of human cells and tissues, mainly using quantitative fluorescence in situ hybridization and Southern blotting, including those derived from patients with progeria-prone Werner syndrome and trisomy 21, and several strains of induced pluripotent stem cells. We discuss the possible merits of using telomere shortness as an indicator, or a new marker, for diagnosis of precancerous states and aging-related disorders. In addition, we describe newly found factors that are thought to impact telomere dynamics, providing a new avenue for examining the unsolved issues related to telomere restoration and maintenance.

Many studies have demonstrated the association between telomere length in mitotic cells and aging, but the relationship between telomere length in post-mitotic cells and aging in human populations has remained largely unclear. In this study, we assessed the dynamics of telomere length (terminal restriction fragment length—TRF) in normal pituitary glands obtained at autopsy from 65 patients aged between 0 and 100 years. The initial length (the value for neonatal pituitary) was 14.2 ± 1.1 kbp (mean of the median TRF value ± SD), being the longest among those for other systemic organs. The annual telomere reduction rates for pituitary (21 bp) were equivalent to or below the lowest values for various cells and tissues. Hence, comparison of TRF lengths among organs revealed that the pituitary gland retained longer telomeres than most other organs throughout life. The median TRF value showed a significant decrease between newborns and the 61–75 age group, but then leveled off or increased slightly in advanced age groups. These data indicate that innate telomere length is highly conserved in the pituitary and suggest that pituitary telomere length provides a good basic indicator for studies of telomere biology. Electronic supplementary material The online version of this article (doi:10.1007/s11357-011-9280-y) contains supplementary material, which is available to authorized users.

Telomeres are repetitive G-rich DNA sequences located at the ends of chromosomes. Chromosomal and genomic instability due to telomere dysfunction plays an important role in carcinogenesis. To study telomere shortening in the oesophageal epithelium of alcoholics, we measured the telomere lengths of basal and parabasal cells in comparison with those of non-alcoholics using Q-FISH and our original software, Tissue Telo, and also assessed histological inflammation. Telomeres in basal cells were significantly shorter in alcoholics than in age-matched normal controls. Prominent histological findings of chronic inflammation were not evident in either alcoholics or non-alcoholics. Our finding that telomeres in the oesophageal epithelium are shorter in alcoholics than in non-alcoholics indicates that telomere shortening may be associated with the frequent occurrence of squamous cell carcinoma in alcoholics. Further studies to clarify the reason for the large annual loss of telomere length with rapid turnover or lower telomerase activity in the oesophageal epithelium of alcoholics will be necessary.

We monitored the telomere lengths and chromosomal instability characteristics of fibroblasts at different population doubling levels (PDLs) to gain further insight into the role of telomere shortening in chromosomal instability. We used 7 normal diploid human fibroblast strains (TIG-1, 3, 7, 103, 104, 112, and 114) and a quantitative fluorescence in situ hybridization method to measure telomere lengths of the p- and q-arms of individual chromosomes. We also enumerated morphologic signs of chromosomal instability, including fusion or loss of chromosomes, and anaphase bridges. In strains TIG-1, 3, 7, 103, and 114 at the late (phase 3) stage (≧40PDLs), 29 (96.6%) of 30 fusions were associated with one or both of the chromosomal arms that bear significantly shorter telomeres in those populations. In TIG-1 at 62PDL, 6 fusions were associated with Xq (n=3), 21q (n=3), and other (n=6) chromosomes. Xq and 21q had significantly shorter telomeres, and anaphase bridges were often associated with chromosomes X and/or 21 (74.6%). Our results indicate that chromosomes having excessively shortened telomeres at late PDLs begin to show features of instability such as fusions and anaphase bridges.

We reviewed our methodology and results of telomere measurements, with reference to telomere length and aging. Human tissues always showed telomere shortening with age, except for the brain and myocardium. Yearly rates of telomere length reduction in various tissues were mostly within the range 20-60 bp, and thus compatible with that expected from only one round of mitosis. It was suggested that when telomeres were found to be longer in any specific organ in a given individual, then the other organs in that individual would also have longer telomeres. Using the quantitative fluorescence in situ hybridization (Q-FISH) method for telomere measurement, we were able to measure the telomere lengths of various cell types within tissues. Here we summarize the results obtained for various cell types in the stomach, tongue and breast. Our Q-FISH method using our original software program "Tissue Telo" is excellent for measuring telomere lengths using tissue sections and PNA probes.

Chromosomal and genomic instability due to telomere dysfunction is known to play an important role in carcinogenesis. To study telomere dysfunction in the surrounding background epithelium of squamous cell carcinoma in situ (CIS) of the oesophagus, we measured telomere lengths of basal and parabasal cells of epithelia with and without CIS using quantitative fluorescence in situ hybridization (Q-FISH) and our original software, Tissue Telo. Additionally, we assessed histological inflammation and the anaphase bridge index. In non-cancerous epithelium, telomeres in basal cells were significantly longer than those in parabasal cells, whereas CIS showed a homogeneous telomere pattern in the basal and parabasal cells. Telomeres in basal and parabasal cells were significantly shorter in the background with CIS than in epithelium from age-matched normal controls. Significant negative correlation was observed between the normalized telomere : centromere ratio (reflected telomere length) and the anaphase bridge index in non-cancerous epithelia from both normal controls and the CIS background with no histological inflammation. These findings indicate that tissue stem cells may be located among basal cells, and that telomere length distribution in component cell types differs between CIS and non-cancerous epithelium. We have demonstrated conclusively that oesophageal CIS arises from epithelium with short telomeres and chromosomal instability in the absence of histological inflammation.

Telomere shortening is thought to be associated with genetic instability. The purpose of this study was to measure telomere length in a series of Barrett's adenocarcinomas (BAs), focusing on the telomere/centromere fluorescent intensity ratio (TCR) with tissue quantitative fluorescent in situ hybridization (Q-FISH).A total of 11 cases of BA were evaluated for upper esophagus (UE), lower esophagus (LE), Barrett's mucosa (BM), BA, and gastric cardiac mucosa (GC). Q-FISH was performed using two kinds of peptide nucleic acid probe, specific for telomeres and centromeres. The sections were analyzed with a CCD camera and original software (Tissue Telo) for measuring TCR. In addition, Laser Capture Microdissection and GeneScan were implemented for evaluation of genetic instability.The TCR values in BM and, to a lesser extent, BA were significantly lower than those in the other tissues, particularly in heterozygosity (LOH)-positive cases. However, no significant difference was evident between microsatellite instability (MSI)-positive and -negative groups.In our study of BA series, telomere length appeared to change with the degree of histological atypia, with decreases linked to LOH.

We investigated the telomere lengths of individual cell types in lingual mucosa using an improved tissue quantitative fluorescence in situ hybridization (Q-FISH) method. Our tissue Q-FISH method compensates for partially cut nuclei in a tissue section by using the telomere:centromere ratio (TCR). We normalized our TCR measurements (NTCR) using a section from a block of cultured cells placed on the same slide, thus improving the accuracy and reproducibility of the results. Normal lingual mucosa was obtained from 21 autopsied individuals. Immunohistochemistry showed positivity mainly for p27, p63, and CK19 in basal cells, and for Ki-67 in parabasal cells. Q-FISH revealed that NTCR was significantly highest in basal cells and lowest in prickle cells, and also that telomere length regressed at a certain rate in each cell type, firstly. Significant correlations of NTCR among the three epithelial cell types were demonstrated. The present findings appear to support the theory that stem cells exist in the basal layer of the lingual epithelium. The reduction of telomere length with age and in each cell layer is consistent with the telomere biology theory of cell proliferation and differentiation in oral mucosa.

Many studies have demonstrated the association between telomere length in mitotic cells and carcinogenesis and mortality, but little attention has been focused on post-mitotic cells and human life expectancy. We assessed the relationship between telomere length in cerebral gray and white matter and longevity in 72 autopsied Japanese patients aged 0–100 years using Southern blot hybridization. The mean telomere lengths in the gray and white matter were 12.3 ± 2.5 kilobase pairs and 11.4 ± 2.1 kilobase pairs, respectively. The mean telomere lengths in 60–69 year decadal group were less than those of neonates, and declined further in the 70–79-year age group, but those in groups of further advanced age were longer than in the 70–79 year group (70–79 < 80–89 < 90–100 years of age). Thus, the 90–100-year age group possessed significantly longer telomeres than the 70s (p = 0.029). Autopsy protocols showed a decrease in the rate of cancer death in individuals in their 80s (p = 0.041) and 90s (p = 0.017) versus those in their 60s, and in their 80s the mean telomere length in the gray matter from cancer death patients was significantly shorter than that of patients who died of other diseases (p = 0.04). These data suggest that innate telomere lengths are maintained very well in the cerebrum, and are associated with longevity. Our study lends indispensable support to the hypothesis that longer telomeres protect the genome from instability (a major cause of carcinogenesis) and are beneficial for longevity.

We investigated progressive telomere shortening in normal human epidermis and lingual epithelium during aging, and attempted, in particular, to ascertain whether the telomere shortening that accompanies aging occurs at the same rate in different tissues. We studied telomeric DNA integrity, and estimated annual telomere loss, in 52 specimens of epidermis and 48 specimens of lingual epithelium collected at autopsy from subjects who had died at ages between 0 and 101 y. Most of the DNA samples were measured twice by southern blot hybridization. In addition, the correlation between telomere lengths in the two types of tissues was examined. The telomere reduction rates in epidermis and lingual epithelium were 36 bp and 30 bp per y, respectively, and these were significantly different. The rates obtained by the second measurements in epidermis and lingual epithelium were 39 and 32 bp per y, respectively, and these were also significantly different. The mean telomere lengths in the epidermis of eight neonates and the lingual epithelium of seven neonates were 13.2+/-1.0 and 13.8+/-1.0 kb, respectively. Comparison of telomere lengths in the two tissues for 41 paired samples showed that the mean telomere length in the epidermis (10.7+/-2.3 kb) was less than that in the lingual epithelium (12.4+/-2.5 kb); however, statistical analysis revealed a very significant relationship between epidermal and lingual epithelial telomere length (r=0.842, p0.0001). These results indicate that the telomeres in epidermis and lingual epithelium are characterized by tissue-specific loss rates.

We have reported that telomere fluorescence units (TFUs) of established induced pluripotent stem cells (iPSCs) derived from human amnion (hAM933) and fetal lung fibroblasts (MRC-5) were significantly longer than those of the parental cells, and that the telomere extension rates varied quite significantly among clones without chromosomal instability, although the telomeres of other iPSCs derived from MRC-5 became shorter as the number of passages increased along with chromosomal abnormalities from an early stage. In the present study we attempted to clarify telomere dynamics in each individual chromosomal arm of parental cells and their derived clonal human iPSCs at different numbers of passages using quantitative fluorescence in situ hybridization (Q-FISH). Although no specific arm of any particular chromosome appeared to be consistently shorter or longer than most of the other chromosomes in any of the cell strains, telomere elongation in each chromosome of an iPSC appeared to be random and stochastic. However, in terms of the whole genome of any specific cell, the telomeres showed overall elongation associated with iPSC generation. We have thus demonstrated the specific telomere dynamics of each individual chromosomal arm in iPSCs derived from parental cells, and in the parental cells themselves, using Q-FISH.

Along with the increasing need for living-donor liver transplantation (LDLT), the issue of organ shortage has become a serious problem. Therefore, the use of organs from elderly donors has been increasing. While the short-term results of LDLT have greatly improved, problems affecting the long-term outcome of transplant patients remain unsolved. Furthermore, since contradictory data have been reported with regard to the relationship between donor age and LT/LDLT outcome, the question of whether the use of elderly donors influences the long-term outcome of a graft after LT/LDLT remains unsettled. To address whether hepatocyte telomere length reflects the outcome of LDLT, we analyzed the telomere lengths of hepatocytes in informative biopsy samples from 12 paired donors and recipients (grafts) of pediatric LDLT more than 5 years after adult-to-child LDLT because of primary biliary atresia, using quantitative fluorescence in situ hybridization (Q-FISH). The telomere lengths in the paired samples showed a robust relationship between the donor and grafted hepatocytes (r = 0.765, p = 0.0038), demonstrating the feasibility of our Q-FISH method for cell-specific evaluation. While 8 pairs showed no significant difference between the telomere lengths for the donor and the recipient, the other 4 pairs showed significantly shorter telomeres in the recipient than in the donor. Multiple regression analysis revealed that the donors in the latter group were older than those in the former (p = 0.001). Despite the small number of subjects, this pilot study indicates that donor age is a crucial factor affecting telomere length sustainability in hepatocytes after pediatric LDLT, and that the telomeres in grafted livers may be elongated somewhat longer when the grafts are immunologically well controlled.

Progressive telomere shortening with aging was studied in the normal liver tissue of 94 human subjects aged between 0 and 101 years old to determine the rate of telomere loss in 1 year. Telomere length demonstrated accelerated shortening with reduction of 55 base pairs (bp) per year. The mean telomere length in five neonates was 12.9 +/- 2.6 kilobase pairs (kbp), and that in one centenarian was 8.3 kbp. Mean telomere lengths by age group were 13.2 +/- 2.0 kbp (or = 8 years; 10 subjects), 7.8 +/- 1.9 kbp (40-79 years; 29 subjects), and 7.5 +/- 2.0 kbp (or = 80 years; 53 subjects), with reduction thus appearing to show slowing on the attainment of middle age. The difference of mean telomere lengths for two groups with or without advanced malignancies of other than liver origin was not significant in the older two groups. Despite the slow turnover of liver tissue, the overall reduction rate of telomere length decrease in 1 year was almost the same as that of digestive tract mucosa, with its very rapid renewal.

Background and Objectives Telomerase is a ribonucleoprotein that synthesizes telomeric DNA. Immortalized and carcinoma cells show no loss of telomere length during cell division. Telomerase activity has been demonstrated in carcinomas of various organs, but not in nonneoplastic tissues. In patients with esophageal carcinoma, no data have been reported concerning the relationship between telomerase activity and clinicopathological findings. Materials and Methods Esophageal carcinomas from 31 patients and normal esophageal mucosae from 92 patients were examined. Telomeric Repeat Amplification Protocol assay to detect telomerase activity and Southern blot analysis to examine telomere length were performed. Results Of the 31 carcinomas, 27 (87%) had detectable telomerase activity. Twenty-one (23%) of the 92 normal esophageal mucosae from autopsied patients also had detectable telomerase activity. There was no difference between stage and outcome and absence or presence of telomerase activity. No difference in terminal restriction fragment (TRF) length was observed between carcinomas with and without telomerase activity. Conclusion Telomerase activity was demonstrated in a considerable number of normal esophageal mucosae. This suggests the possibility of a high frequency of false positivity if the presence of telomerase activity alone is used as a tumor-specific marker. J. Surg. Oncol. 1997;66:88–92. © 1997 Wiley-Liss, Inc.

Chromosomal and genomic instability due to telomere dysfunction is known to play an important role in carcinogenesis. To study telomere shortening in the epidermis surrounding actinic keratosis, we measured telomere lengths of basal, parabasal, and suprabasal cells in epidermis with actinic keratosis (actinic keratosis group, n = 18) and without actinic keratosis (sun-protected, n = 15, and sun-exposed, n = 13 groups) and in actinic keratosis itself as well as in dermal fibroblasts in the 3 groups, using quantitative fluorescence in situ hybridization. Among the 3 cell types, telomeres of basal cells were not always the longest, suggesting that tissue stem cells are not necessarily located among basal cells. Telomeres of basal cells in the sun-exposed group were shorter than those in the sun-protected group. Telomeres in the background of actinic keratosis and in actinic keratosis itself and those of fibroblasts in actinic keratosis were significantly shorter than those in the controls. Our findings demonstrate that sun exposure induces telomere shortening and that actinic keratosis arises from epidermis with shorter telomeres despite the absence of any histologic atypia.

We attempted to clarify myocardial telomere dynamics using samples from 530 autopsied patients using Southern blot analysis. Overall regression analysis demonstrated yearly telomere reduction rate of 20 base pairs in the myocardium. There was a significant correlation between myocardial telomere and aging. Moreover, regression analyses of telomere and heart weight yielded a telomere reduction rate of 3 base pairs per gram and a small but significant correlation between telomere reduction and heart weight was demonstrated. Hearts of autopsied patients who had died of heart disease were significantly heavier than those of patients who had died of cancer or other diseases and heart disease was significantly more correlated with myocardial telomere shortening than cancer or other diseases. Here we show that telomeres in myocardial tissue become shortened with aging and heart disease and that heart disease was associated with a gain of heart weight and telomere shortening in the myocardium.

Here we attempted to clarify telomere metabolism in parental cells and their derived clonal human induced pluripotent stem cells (iPSCs) at different passages using quantitative fluorescence in situ hybridization (Q-FISH). Our methodology involved estimation of the individual telomere lengths of chromosomal arms in individual cells within each clone in relation to telomere fluorescence units (TFUs) determined by Q-FISH. TFUs were very variable within the same metaphase spread and within the same cell. TFUs of the established iPSCs derived from human amnion (hAM933 iPSCs), expressed as mean values of the median TFUs of 20 karyotypes, were significantly longer than those of the parental cells, although the telomere extension rates varied quite significantly among the clones. Twenty metaphase spreads from hAM933 iPSCs demonstrated no chromosomal instability. The iPSCs established from fetal lung fibroblasts (MRC-5) did not exhibit telomere shortening and chromosomal instability as the number of passages increased. However, the telomeres of other iPSCs derived from MRC-5 became shorter as the number of passages increased, and one (5%) of 20 metaphase spreads showed chromosomal abnormalities including X trisomy at an early stage and all 20 showed abnormalities including X and 12 trisomies at the late stage.

Progressive telomere shortening with aging was studied using normal esophageal mucosal specimens from 177 human subjects aged between 0 and 102 years (yrs). We observed age-related shortening of the telomere, at a rate of 60 base pairs (bp) per year (yr). The mean telomere length of 12 neonates was 15.2 kilobase pairs (kbp) and that of 2 centenarians was 9.3 kbp. Mean (±SD) telomere lengths were 14.9±1.3, 14.0±1.8, 10.1±3.7, 10.4±3.3 and 9.5±3.1 kbp for the age groups less than 2 yrs, 2–20 yrs, 21–60 yrs, 61–80 yrs and 81–102 yrs, respectively. The variation in telomere length among individuals in the same age group was greater for the 3 older groups than for the 2 younger groups, as shown by the SDs. Furthermore, older individuals had greater telomere length variation than younger individuals, based on the lengths of DNA digested smears. Although the telomere length decreased significantly with aging at the rate of 60 bp per yr, differences in the mean telomere lengths between the 3 older age groups were not significant. Rapid shortening occurred in the young generations and there was no further substantial decrease in the esophageal mucosa after 60 yrs of age. Compared to the very rapid renewal rate of the esophageal epithelial cells, the annual reduction rate in telomere length was very low. These findings support the hypothesis that germ cells in the esophageal epithelium have a mechanism to lengthen telomeres.

Trisomies 18 and 21 are genetic disorders in which cells possess an extra copy of each of the relevant chromosomes. Individuals with these disorders who survive birth generally have a shortened life expectancy. As telomeres are known to play an important role in the maintenance of genomic integrity by protecting the chromosomal ends, we conducted a study to determine whether there are differences in telomere length at birth between individuals with trisomy and diploidy, and between trisomic chromosomes and normal chromosomes. We examined samples of peripheral blood lymphocytes (PBLs) from 31 live neonates (diploidy: 10, trisomy 18: 10, trisomy 21: 11) and estimated the telomere length of each chromosome arm using Q-FISH. We observed that the telomeres of trisomic chromosomes were neither shorter nor longer than the mean telomere length of chromosomes as a whole among subjects with trisomies 18 and 21 (intra-cell comparison), and we were unable to conclude that there were differences in telomere length between 18 trisomy and diploid subjects, or between 21 trisomy and diploid subjects (inter-individual comparison). Although it has been reported that telomeres are shorter in older individuals with trisomy 21 and show accelerated telomere shortening with age, our data suggest that patients with trisomies 18 and 21 may have comparably sized telomeres. Therefore, it would be advisable for them to avoid lifestyle habits and characteristics such as obesity, cigarette smoking, chronic stress, and alcohol intake, which lead to marked telomere shortening.

Many data pertaining to the accelerated telomere loss in cultured cells derived from Werner syndrome (WS), a representative premature aging syndrome, have been accumulated. However, there have been no definitive data on in vivo telomere shortening in WS patients. In the present study, we measured terminal restriction fragment (TRF) lengths of 10 skin samples collected from extremities of 8 WS patients aged between 30 and 61 years that had been surgically amputated because of skin ulceration, and estimated the annual telomere loss. Whereas the values of TRF length in younger WS patients (in their thirties) were within the normal range, those in older WS patients were markedly shorter relative to non-WS controls. Regression analyses indicated that the TRF length in WS was significantly shorter than that in controls (p < 0.001). Furthermore, we found that TRF lengths in muscle adjacent to the examined epidermis were also significantly shorter than those of controls (p = 0.047). These data demonstrate for the first time that in vivo telomere loss is accelerated in systemic organs of WS patients, suggesting that abnormal telomere erosion is one of the major causes of early onset of age-related symptoms and a predisposition to sarcoma and carcinoma in WS.

Telomeres are repetitive G-rich DNA sequences located at the ends of chromosomes. Chromosomal and genomic instability due to telomere dysfunction plays an important role in carcinogenesis. To study telomere shortening in the oesophageal epithelium of alcoholics, we measured the telomere lengths of basal and parabasal cells in comparison with those of non-alcoholics using Q-FISH and our original software, Tissue Telo, and also assessed histological inflammation. Telomeres in basal cells were significantly shorter in alcoholics than in age-matched normal controls. Prominent histological findings of chronic inflammation were not evident in either alcoholics or non-alcoholics. Our finding that telomeres in the oesophageal epithelium are shorter in alcoholics than in non-alcoholics indicates that telomere shortening may be associated with the frequent occurrence of squamous cell carcinoma in alcoholics. Further studies to clarify the reason for the large annual loss of telomere length with rapid turnover or lower telomerase activity in the oesophageal epithelium of alcoholics will be necessary.

We reviewed our methodology and results of telomere measurements, with reference to telomere length and aging. Human tissues always showed telomere shortening with age, except for the brain and myocardium. Yearly rates of telomere length reduction in various tissues were mostly within the range 20-60 bp, and thus compatible with that expected from only one round of mitosis. It was suggested that when telomeres were found to be longer in any specific organ in a given individual, then the other organs in that individual would also have longer telomeres. Using the quantitative fluorescence in situ hybridization (Q-FISH) method for telomere measurement, we were able to measure the telomere lengths of various cell types within tissues. Here we summarize the results obtained for various cell types in the stomach, tongue and breast. Our Q-FISH method using our original software program "Tissue Telo" is excellent for measuring telomere lengths using tissue sections and PNA probes.

Chromosomal and genomic instability due to telomere dysfunction is known to play an important role in carcinogenesis. To study telomere dysfunction in the surrounding background epithelium of squamous cell carcinoma in situ (CIS) of the oesophagus, we measured telomere lengths of basal and parabasal cells of epithelia with and without CIS using quantitative fluorescence in situ hybridization (Q-FISH) and our original software, Tissue Telo. Additionally, we assessed histological inflammation and the anaphase bridge index. In non-cancerous epithelium, telomeres in basal cells were significantly longer than those in parabasal cells, whereas CIS showed a homogeneous telomere pattern in the basal and parabasal cells. Telomeres in basal and parabasal cells were significantly shorter in the background with CIS than in epithelium from age-matched normal controls. Significant negative correlation was observed between the normalized telomere : centromere ratio (reflected telomere length) and the anaphase bridge index in non-cancerous epithelia from both normal controls and the CIS background with no histological inflammation. These findings indicate that tissue stem cells may be located among basal cells, and that telomere length distribution in component cell types differs between CIS and non-cancerous epithelium. We have demonstrated conclusively that oesophageal CIS arises from epithelium with short telomeres and chromosomal instability in the absence of histological inflammation.

Critically shortened, dysfunctional telomeres may play a role in the genetic instabilities commonly found in cancer. We analyzed 30 surgical specimens of invasive breast carcinoma from women aged 34 to 91 years and estimated telomere lengths as telomere-to-centromere ratio values in the 5 different cell types comprising breast tissue in order to clarify telomere length variations within and between individuals using our tissue quantitative fluorescence in situ hybridization method. We obtained 3 novel findings. (1) In corresponding normal tissues, telomere length decreased in the order myoepithelial cells > normal-appearing fibroblasts > luminal epithelial cells, and telomere lengths were characteristic in these 3 cell types within each individual. (2) As expected, cancer cells had significantly shorter telomeres than myoepithelial cells (P < .0001) and normal-appearing fibroblasts (P = .0161), but there was no significant difference in telomere length between luminal cells and cancer cells (P = .6270). (3) Fibroblasts adjacent to cancer had longer telomeres than normal-appearing fibroblasts distant from cancer (P < .0001). This study, which represents the first reported assessment of telomere length variations in the 5 cell types comprising breast tissue within and between individuals, revealed that normal luminal epithelial cells and cancer cells had the shortest telomeres. Our new findings indicate that telomeres of background luminal cells are as short as those of cancer cells. Tissue quantitative fluorescence in situ hybridization, applicable to analysis of individual cells in tissue sections, is considered to be a powerful technique with considerable promise for studies in oncology.

Previous studies of telomeres and telomerase have focused mostly on mammals, and data for other vertebrates are limited. We analyzed both telomere length (terminal restriction fragment length) and telomerase activity in a small freshwater teleost fish, the medaka (Oryzias latipes), and found that the telomeres shorten during ageing despite the fact that a considerable amount of telomerase activity is ubiquitously detectable throughout the life of the fish. Since the telomere attrition rate during development was greater than that in adulthood, telomere length is inversely correlated with the increase in body length. The difference in telomere length among medaka individuals was similar to that in humans, and the individual specific differences were evident even at the earliest embryonic stage. Telomerase activity was ubiquitously detectable not only in the body of the embryo but also in the systemic organs of mature individuals throughout their entire life span. These data suggest that telomere attrition during ageing in medaka, which is similar to that in humans, may be a major factor determining their mortality, and that telomere maintenance through strong telomerase activity may be required for the characteristic lifelong continuous growth of this fish.

Critically shortened telomeres make chromosomes susceptible to the instability and widespread cytogenetic alterations that characterize most human cancers. We hypothesized that the very rapid cell proliferation observed in esophageal squamous cell carcinomas might accelerate telomere shortening and chromosomal instability associated with carcinogenesis. We used a number of telomere measurement techniques including quantitative fluorescence in situ hybridization (Q-FISH) to compare chromosomal aberrations and telomere lengths of individual chromosomes in esophageal squamous cell carcinomas (ESCCs) and nearby non-neoplastic esophageal epithelium (NNEE) cells. Our results showed that the mean telomere length in ESCC cells was significantly less than that in adjacent NNEE cells, and that telomeres in all NNEE cells were significantly shorter than those in normal esophageal epithelium (reported previously). In addition, there was no evidence linking telomere shortening of a particular chromosome to field cancerization in ESCC. However, a mechanistic link between telomere shortening and chromosomal instability was supported by a higher frequency of anaphase/telophase bridges and an increase in the frequency of aneuploidy. This study furthers our understanding of the mechanism by which telomere shortening and chromosomal instability lead to carcinogenesis and field cancerization in the esophagus.

Objective: We have developed a novel method for evaluating telomere length in four different cell types in non-cancerous and cancerous mucosal tissue from 15 cases of squamous cell carcinoma of the esophagus using tissue quantitative fluorescence in situ hybridization (Q-FISH). We hypothesized that the very rapid cell proliferation observed in esophageal squamous cell carcinomas might accelerate the telomere shortening and chromosomal instability associated with carcinogenesis. Methods: Tissue Q-FISH and the telomere to centromere intensity ratio (TCR) were used to compare telomere shortening in tissue sections taken from esophageal squamous cell carcinomas and adjacent non-cancerous esophageal tissues. Results: The peak percentage of TCR was 1 for the non-cancerous esophageal cell types. Basal layer cells had the longest telomeres in comparison with prickle, cancer, and stromal cells, and strongly expressed hTERT, cytokeratin 14 and CD49f, but not MIB-1. Conclusion: These results suggest the presence of stem cells in the basal layer of the esophagus. Esophageal squamous cell carcinomas also display anaphase bridges, evidencing chromosomal instability.In conclusion, our TCR method can be used to distinguish between benign and malignant tissue in esophageal lesions. In order to apply this approach clinically to individual cases, further studies are in progress.

A large body of evidence supports a key role for telomere dysfunction in carcinogenesis due to the induction of chromosomal instability. To study telomere shortening in precancerous pancreatic lesions, we measured telomere lengths using quantitative fluorescence in situ hybridization in the normal pancreatic duct epithelium, pancreatic intraepithelial neoplasias (PanINs), and cancers. The materials employed included surgically resected pancreatic specimens without cancer (n = 33) and with invasive ductal carcinoma (n = 36), as well as control autopsy cases (n = 150). In comparison with normal ducts, telomere length was decreased in PanIN-1, -2 and -3 and cancer. Furthermore, telomeres were shorter in cancer than in PanIN-1 and -2. Telomere length in cancer was not associated with histological type, lesion location, or cancer stage. PanINs with or without cancer showed similar telomere lengths. The incidences of atypical mitosis and anaphase bridges, which are morphological characteristics of chromosomal instability, were negatively correlated with telomere length. The telomeres in normal duct epithelium became shorter with aging, and those in PanINs or cancers were shorter than in age-matched controls, suggesting that telomere shortening occurs even when histological changes are absent. Our data strongly suggest that telomere shortening occurs in the early stages of pancreatic carcinogenesis and progresses with precancerous development. Telomere shortening and chromosomal instability in the duct epithelium might be associated with carcinogenesis of the pancreas. Determination of telomere length in pancreatic ductal lesions may be valuable for accurate detection and risk assessment of pancreatic cancer.

We developed a novel method for evaluating telomere length in 6 cell types of noncancerous and cancerous mucosal tissues from 11 cases of gastric neoplasm using the quantitative fluorescence in situ hybridization method with telomere and centromere peptide nucleic acid probes. Our telomere length estimates were determined from the background-corrected telomere intensity divided by the background-corrected centromere intensity (telomere-to-centromere ratio). Our results indicated that telomere lengths in each of the cases studied were reduced in turn from fibroblasts to fundic gland cells, to glandular neck cells, and then to surface foveolar cells. However, the telomere lengths of intestinalized cells located among fundic glands were not always shorter than those of the other cell types, as reported previously by others. Helicobacter pylori infection was suggested to induce the telomere shortening seen in the fundic glands. Although the mean telomere lengths varied among the 8 gastric cancer cases, correlation of the telomere lengths with the Ki-67 labeling index was established after normalization with the fibroblast measurements. We conclude that our telomere-to-centromere ratio method can reliably estimate the telomere lengths of the 6 cell types in the gastric mucosa and clarifies the relationship between proliferative activity and the telomere length of cancer cells.

One of the most aggressive human malignancies, anaplastic thyroid carcinoma (ATC), has an extremely poor prognosis that may be explained by its genomic instability. We hypothesized that the very rapid cell turnover observed in ATC might accelerate telomere shortening and chromosomal instability associated with tumor cell malignancy. To compare and measure chromosomal aberrations and telomere shortening in the anaplastic thyroid cancer cell line OCUT-1, we applied quantitative fluorescence in situ hybridization (Q-FISH) techniques. In all 15 metaphases studied, telomere length estimates from Q-FISH of chromosomes in ATC were shorter than those of a fibroblast cell line derived from the stroma adjacent to the carcinoma. OCUT-1 cells display several chromosomal abnormalities, but have a near-normal chromosome complement of 46, XX, making it easy to analyze the karyotype. The karyotype showed 50, XX, +7, +11, der(ll)t(3;ll)(q23;q23)x2, del(12)(pl 1.2p12), +20, +1mar. We analyzed carefully the abnormalities in karyotype of OCUT-1 associated with telomere shortening on each chromosome and expression of subtelomeres. Telomere lengths in the q-arms of the abnormal chromosome del(12)(p11.2p12) were shorter than the average length in the q-arms of the normal chromosome 12 in OCUT-1. Subtelomeres on the abnormal chromosome der(11)t(3;11)(q23;q23)x2 also showed loss of signals on 11p, but there was no loss of signals in the cytogenetically normal trisomies 7 and 20 or the abnormal chromosome del(12)(p11.2p12). Subtelomeres of 3q had eight signals, one pair remaining in place on 3q and another pair on the abnormal 11p. Our findings suggest that telomere shortening and subtelomere loss are correlated with genetic instability in this anaplastic thyroid carcinoma cell line.

One of the most aggressive human malignancies, anaplastic thyroid carcinoma (ATC), has an extremely poor prognosis that may be explained by its genomic instability. We hypothesized that the very rapid cell turnover observed in ATC might accelerate telomere shortening and chromosomal instability associated with tumor cell malignancy. To compare and measure chromosomal aberrations and telomere shortening in the anaplastic thyroid cancer cell line OCUT-1, we applied quantitative fluorescence in situ hybridization (Q-FISH) techniques. In all 15 metaphases studied, telomere length estimates from Q-FISH of chromosomes in ATC were shorter than those of a fibroblast cell line derived from the stroma adjacent to the carcinoma. OCUT-1 cells display several chromosomal abnormalities, but have a near-normal chromosome complement of 46, XX, making it easy to analyze the karyotype. The karyotype showed 50, XX, +7, +11, der(11)t(3;11)(q23;q23)x2, del(12)(p11.2p12), +20, +1mar. We analyzed carefully the abnormalities in karyotype of OCUT-1 associated with telomere shortening on each chromosome and expression of subtelomeres. Telomere lengths in the q-arms of the abnormal chromosome del(12)(p11.2p12) were shorter than the average length in the q-arms of the normal chromosome 12 in OCUT-1. Subtelomeres on the abnormal chromosome der(11)t(3;11)(q23;q23)x2 also showed loss of signals on 11p, but there was no loss of signals in the cytogenetically normal trisomies 7 and 20 or the abnormal chromosome del(12)(p11.2p12). Subtelomeres of 3q had eight signals, one pair remaining in place on 3q and another pair on the abnormal 11p. Our findings suggest that telomere shortening and subtelomere loss are correlated with genetic instability in this anaplastic thyroid carcinoma cell line.

We have conducted systematic studies to measure telomere length in human tissues of all types. Progressive telomere shortening with aging was studied in specimens of normal pancreas obtained at autopsy from 69 subjects aged 0 to 100 yr, and age-related shortening of telomere length at a rate of 36 base pairs (bp) per year was detected. Mean telomere length (±SD) was 13.9 ± 1.4 kilobase pairs (kbp) in 16 neonates, as opposed to 8.4 kbp in 2 centenarians. Mean telomere length (±SD) in four age groups, 0–24, 25–49, 50–74, and 75–100 yr, was 13.5 ± 1.5, 12.3 ± 0.7, 11.3 ± 2.5, and 10.7 ± 1.8, respectively.

Background. A great deal of attention has been focused on telomeres in relation to cellular aging, immortality, and cancer. However, there is no simple link between telomeres and tissue turnover. We recently proposed a hypothesis that telomere shortening with aging and telomere lengths in different organs are characteristic for human individuals. Methods. To test this, telomere lengths were measured using DNA from cerebral cortex, myocardium, liver, renal cortex and spleen tissues obtained from human subjects ranging in age from neonates to centenarians. Results. Regression analyses demonstrated telomere reduction rates of 29–60 base pair (bp) per year in the liver, renal cortex and spleen, but no such decrease in the cerebral cortex and myocardium. Significant correlation was found between tissues within individuals, such as cerebral cortex versus (vs) myocardium, cerebral cortex vs liver, cerebral cortex vs renal cortex, myocardium vs liver, myocardium vs renal cortex, and liver vs renal cortex. In most cases, the longest telomeres were observed in the myocardium and the shortest in the liver or renal cortex. Conclusions. Telomere lengths did not show clear correlation with tissue renewal times in vivo, but rather were characteristic for individuals.