Association between telomere length in the DNA of peripheral blood leukocytes and the propofol dose in anesthesia induction: an observational study

Abstract Introduction: Propofol is a widely used anesthetic and its dose is closely related to aging. Telomere length (TL) is a unique heritable trait, and emerging as a biomarker of aging, health and disease. Telomerase RNA component (TERC) plays an important role in maintaining TL. We proposed a hypothesis that propofol dose in general anesthesia can be predicted by measuring TL before operation, which greatly reduced the risk of anesthesia, especially the elderly. Methods: The association between the propofol dose in anesthesia induction and: TL in the DNA of peripheral blood leukocytes; body weight; sex; difference of the Bispectral Index (BIS) before and after anesthesia induction in patients was evaluated by multivariable linear regression analyses. The mutation at the 5'end or 3'end of TERC was detected. We recruited 100 patients of elective surgery. Results: We found that propofol dose in anesthesia induction was clearly correlated significantly with TL (r = 0.78, p < 0.001), body weight (r = 0.84, p = 0.004), sex (r = 0.83, p= 0.84, p = 0.004), sex (r = 0.83, p = 0.004), and difference of BIS before and after anesthesia induction (r = 0.85, p = 0.029). By comparing the absolute values of standardized regression coefficients (0.58, 0.21, 0.19, and 0.12) of the four variables, it can be seen that TL contributes the most to the propofol dose in anesthesia induction. However, the mutation at the 5' end or 3' end of TERC was not found. Conclusions: These findings provide preliminary evidence that the propofol dose in anesthesia induction was clearly correlated with genetically determined TL. TL may be a promising predictor of the propofol dose, which is beneficial to improve the safety of anesthesia and reduce perioperative complications.

Lamin B1 regulates the growth of hepatocellular carcinoma cells by influencing telomerase activity / 生物工程学报

Lamin B1 (LMNB1) is highly expressed in liver cancer tissues, and its influence and mechanism on the proliferation of hepatocellular carcinoma cells were explored by knocking down the expression of the protein. In liver cancer cells, siRNAs were used to knock down LMNB1. Knockdown effects were detected by Western blotting. Changes in telomerase activity were detected by telomeric repeat amplification protocol assay (TRAP) experiments. Telomere length changes were detected by quantitative real-time polymerase chain reaction (qPCR). CCK8, cloning formation, transwell and wound healing were performed to detect changes in its growth, invasion and migration capabilities. The lentiviral system was used to construct HepG2 cells that steadily knocked down LMNB1. Then the changes of telomere length and telomerase activity were detected, and the cell aging status was detected by SA-β-gal senescence staining. The effects of tumorigenesis were detected by nude mouse subcutaneous tumorigenesis experiments, subsequent histification staining of tumors, SA-β-gal senescence staining, fluorescence in situ hybridization (FISH) for telomere analysis and other experiments. Finally, the method of biogenesis analysis was used to find the expression of LMNB1 in clinical liver cancer tissues, and its relationship with clinical stages and patient survival. Knockdown of LMNB1 in HepG2 and Hep3B cells significantly reduced telomerase activity, cell proliferation, migration and invasion abilities. Experiments in cells and tumor formation in nude mice had demonstrated that stable knockdown of LMNB1 reduced telomerase activity, shortened telomere length, senesced cells, reduced cell tumorigenicity and KI-67 expression. Bioinformatics analysis showed that LMNB1 was highly expressed in liver cancer tissues and correlated with tumor stage and patient survival. In conclusion, LMNB1 is overexpressed in liver cancer cells, and it is expected to become an indicator for evaluating the clinical prognosis of liver cancer patients and a target for precise treatment.

Interaction of polycyclic aromatic hydrocarbon DNA adducts and telomere length on missed abortion / 中华预防医学杂志

Objective: To analyze the contribution and interaction of polycyclic aromatic hydrocarbons (PAH)-DNA adducts and changes of telomere length (TL) on missed abortion. Methods: From March to December 2019, patients with missed abortion in the First Hospital of Shanxi Medical University and pregnant women with normal pregnancy but voluntary abortion in the same department during the same period were selected and divided into a case group and a control group. Questionnaire was used to investigate the general situation and the pregnancy situation of the subjects. The abortion villi were collected and the content of PAH-DNA adducts and TL was detected. Logistic regression model was used to analyze the associated factors of missed abortion. R epiR package and Mediation package were used to analyze the effect and relationship between PAH-DNA adducts and TL on missed abortion. Results: The age of the subjects was(29.92±5.69)years old. The M(Q1,Q3)of PAH-DNA adducts was 453.75(404.61, 504.72) pg/ml. The M(Q1,Q3)of TL was 1.21(0.77, 1.72). The content of PAH-DNA adducts in the case group was higher than that in the control group (Z=-2.10, P=0.036), while the TL was lower than that in the control group (Z=-4.05, P<0.001). Multivariate logistic regression showed that low, medium and high levels of PAH-DNA adducts (OR=3.17,95%CI:1.41-7.14;OR=2.85,95%CI:1.25-6.52;OR=2.46,95%CI:1.07-5.64), and long, medium and short levels of TL (OR=2.50,95%CI:1.11-5.63;OR=3.32,95%CI:1.45-7.56;OR=3.22,95%CI:1.42-7.26) were all risk factors for missed abortion. The medium level of PAH-DNA adducts had a 2.76-fold higher risk of shortened TL than those with the lowest level, and no mediating role of TL was found. The stratified analysis showed that when the TL level was longer (>1.21), the low and high levels of PAH-DNA adducts were associated with missed abortion (all P<0.05); when the TL level was shorter (<1.21), the medium level of PAH-DNA adducts was associated with abortion (P=0.025). At lower levels of PAH-DNA adducts, no effect of TL on missed abortion was observed, while, at higher levels, TL was strongly associated with missed abortion (OR=7.50,95%CI:1.95-28.82;OR=6.04,95%CI:1.54-23.65;OR=9.05,95%CI:2.34-35.04). The interaction analysis found that the AP was 0.72 (95%CI: 0.46-0.99), and the SI was 5.21 (95%CI: 2.30-11.77). Conclusion: The high level of PAH-DNA adducts and shortened TL may increase the risk of missed abortion, and there may be a positive additive interaction between the two factors on missed abortion.

Estratégias anti-aging baseadas em moléculas químicas naturais como potentes ativadores de telomerase / Anti-aging strategies based on natural chemical molecules as potent telomerase activators / Estrategias antienvejecimiento basadas en moléculas químicas naturales como potentes activadores de la telomerasa

Mesmo em tempos modernos, os grandes avanços tecnológicos não permitem de forma comprovada retardar o envelhecimento nos seres humanos. Neste sentido, uma das estratégias é o uso moléculas químicas naturais que possuem a ação de ativadores de telomerase, uma vez de que a telomerase é uma ribonucleoproteína transcriptase reversa que possui a função de alongar os telômeros e neutralizar a erosão normal dos telômeros. Neste contexto, este estudo de revisão dedicou-se a aprofundar o conhecimento sobre o uso de moléculas químicas naturais derivadas de plantas que possuem função de ativadores de telomerase para atividade anti-aging. Inúmeras moléculas têm sido propostas e, estudas os seus mecanismos com o intuito de desenvolver novas ferramentas para prevenir/retardar e tratar doenças relacionadas a idade e o envelhecimento. Adicionalmente, o uso de moléculas como ativadores da telomerase têm sido um meio de prolongar o encurtamento dos temoleros, como no caso, de moléculas isolada da erva Astragalus membranaceus (TA-65), curcumina, silbinina e alicina; ademais, outras moléculas de origem natural possuem atividade anti-aging comprovadas, conforme reportadas nesta revisão. Sendo assim, a procura por biomarcadores à base de compostos químicos naturais que estimulem a telomerase, a fim de prolongar a vida dos telômero e assim, retardar o processo de envelhecimento do organismo têm despertado o interesse de diversos pesquisadores ao redor do mundo.

Even in modern times, the great technological advances do not allow in a proven way to delay aging in humans. In this sense, one of the strategies is the use of natural chemical molecules that have telomerase activators, since telomerase is a ribonucleoprotein reverse transcriptase that has the function of lengthening telomeres and neutralizing the normal erosion of telomeres. In this context, this review study was dedicated to deepening the knowledge about the use of natural chemical molecules derived from plants that have telomerase activator function for anti-aging activity. Numerous molecules have been proposed and their mechanisms studied in order to develop new tools to prevent/delay and treat aging-related diseases. Additionally, the use of molecules as telomerase activators has been a means of prolonging the shortening of temolers, as in the case of molecules isolated from the herb Astragalus membranaceus (TA-65), curcumin, silbinin and allicin; in addition, other molecules of natural origin have proven anti-aging activity, as reported in this review. Therefore, the search for biomarkers based on natural chemical compounds that stimulate telomerase in order to prolong the life of telomeres and, thus delay the aging process of the organism has aroused the interest of several researchers around the world.

Aún en los tiempos modernos, los grandes avances tecnológicos no permiten de manera comprobada retrasar el envejecimiento en los humanos. En este sentido, una de las estrategias es el uso de moléculas químicas naturales que tengan activadores de la telomerasa, ya que la telomerasa es una ribonucleoproteína transcriptasa inversa que tiene la función de alargar los telómeros y neutralizar la erosión normal de los telómeros. En este contexto, este estudio de revisión se dedicó a profundizar en el conocimiento sobre el uso de moléculas químicas naturales derivadas de plantas que tienen función activadora de la telomerasa para la actividad antienvejecimiento. Se han propuesto numerosas moléculas y se han estudiado sus mecanismos para desarrollar nuevas herramientas para prevenir/retrasar y tratar enfermedades relacionadas con el envejecimiento. Adicionalmente, el uso de moléculas como activadores de la telomerasa ha sido un medio para prolongar el acortamiento de temolers, como es el caso de moléculas aisladas de la hierba Astragalus membranaceus (TA-65), curcumina, silbinina y alicina; además, otras moléculas de origen natural han demostrado actividad antienvejecimiento, como se reporta en esta revisión. Por ello, la búsqueda de biomarcadores basados en compuestos químicos naturales que estimulen la telomerasa para prolongar la vida de los telómeros y así retrasar el proceso de envejecimiento del organismo ha despertado el interés de varios investigadores a nivel mundial.

Association between leukocyte telomere length and sex by quantile regression analysis

ABSTRACT Introduction: Telomere length (TL) is a biomarker of cellular proliferative history. In healthy individuals, leukocyte TL shortens with age and associates with the lifespan of men and women. However, most of studies had used linear regression models to address the association of the TL attrition, aging and sex. Methods: We evaluated the association between the TL, aging and sex in a cohort of 180 healthy subjects by quantile regression. The TL of nucleated blood cells was measured by fluorescent in situ hypridization (flow-FISH) in a cohort of 89 men, 81 women, and 10 umbilical cord samples. The results were validated by quantitative polymerase chain reaction (qPCR) and compared to a linear regression analysis. Results: By quantile regression, telomere dynamics slightly differed between sexes with aging: women had longer telomeres at birth and slower attrition rate than men until the sixth decade of life; after that, TL eroded faster and became shorter than that in men. These differences were not observed by linear regression analysis, as the overall telomere attrition rates in women and men were similar (42 pb per year, p < 0.0001 vs. 45 pb kb per year, p < 0.0001). Also, qPCR did not recapitulate flow-FISH findings, as the telomere dynamics by qPCR followed a linear model. Conclusion: The quantile regression analysis accurately reproduced a third-orderpolynomial TL attrition rate in both women and men, but it depended on the technique applied to measure TL. The Flow-FISH reproduced the expected telomere dynamics through life and, differently from the qPCR, was able to detect the subtle TL variations associated with sex and aging.

Research progress of lung aging in chronic respiratory diseases / 生理学报

Cell aging is an extremely complex process, which is characterized by mitochondrial structural dysfunction, telomere shortening, inflammatory microenvironment, protein homeostasis imbalance, epigenetic changes, abnormal DNA damage and repair, etc. Aging is usually accompanied by structural and functional damage of tissues and organs which further induces the occurrence and development of aging-related diseases. Aging includes physiological aging caused by increased age and pathological aging induced by a variety of factors. Noteworthy, as a target organ directly contacting with the outside air, lung is more prone to various stimuli, causing pathological premature aging which is lung aging. Studies have found that there is a certain proportion of senescent cells in the lungs of most chronic respiratory diseases. However, the underlying mechanism by which these senescent cells induce lung senescence and their role in chronic respiratory diseases is still obscure. This paper focuses on the causes and classification of lung aging, the internal mechanism of lung aging involved in chronic respiratory diseases, and the application of anti-aging treatments in chronic respiratory diseases. We hope to provide new research ideas and theoretical basis for the clinical prevention and treatment in chronic respiratory diseases.

Telomere length: biological marker of cellular vitality, aging, and health-disease process

SUMMARY The aging process occurs due to the decline of vital physiological functions and adaptability of the body, being influenced by genetics and lifestyle. With advances in genetics, biological aging can be calculated by telomere length. Telomeres are regions at the ends of chromosomes that play a role in the maintenance and integrity of DNA. With biological aging, telomere shortening occurs, causing cellular senescence. Several studies show that shorter telomeres are associated with acute and chronic diseases, stress, addictions, and intoxications. Even in the current COVID-19 pandemic, telomere shortening is proposed as a marker of severity in individuals infected by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). On the other hand, healthy lifestyle habits increase telomere length and balance of various cellular functions, preventing diseases.

The Effect and Mechanism of Novel Telomerase Inhibitor Nilo 22 on Leukemia Cells / 中国实验血液学杂志

OBJECTIVE@#To investigate the cytotoxic effect and its mechanism of the micromolecule compound on the leukemia cells.@*METHODS@#The cytotoxic effects of 28 Nilotinib derivatives on K562, KA, KG, HA and 32D cell lines were detected by MTT assays, and the compound Nilo 22 was screen out. Cell apoptosis and cell cycle on leukemia cells were detected by flow cytometry. The effect of compound screened out on leukemogenesis potential of MLL-AF9 leukemia mice GFP@*RESULTS@#Nilo 22 serves as the most outstanding candidate out of 28 Nilotinib derivatives, which impairs leukemia cell lines, but spares normal hematopoietic cell line. Comparing with Nilotinib, Nilo 22 could induce the apoptosis of GFP@*CONCLUSION@#Nilo 22 shows a significant cytotoxic effect on mice and human leukemia cells, especially for drug resistance cells. Nilo 22 is a promising anti-leukemia agent to solve the common clinical problems of drug resistance and relapse of leukemia.

Telómeros y telomerasa: marcadores biológico-genómicos de la vitalidad-actividad celular, de la longevidad-envejecimiento y del proceso salud-enfermedad / Telomeres and telomerase: biological-genomic markers of cell vitality-activity, longevity-aging and the health-disease process

El proceso de envejecimiento se produce por la disminución de las funciones fisiológicas y de la capacidad de adaptación del organismo, siendo influenciado por la genética y el estilo de vida. Actualmente, con los avances de la genética, el envejecimiento biológico se puede calcular por la longitud de los telómeros ('telomere lenght'). Los telómeros son regiones en los extremos de los cromosomas que juegan un papel en el mantenimiento y la integridad del ADN. Con el envejecimiento biológico, se produce el acortamiento de los telómeros, causando la senescencia celular. Numerosos estudios evidencian que telómeros más cortos están asociados a enfermedades crónicas, a vicios y a intoxicaciones. Por otro lado, hábitos de vida saludables propician el aumento de la longitud de los telómeros y el equilibrio de las diversas funciones celulares, previniendo enfermedades. Por lo tanto, los telómeros funcionan como un biomarcador de la vitalidad del organismo.(AU)

Association between socioeconomic markers and adult telomere length differs according to sex: Pro-Saúde study

Understanding the social determinants of telomere length is critical to evaluate the risk of early biological aging. We investigated sex differences on the association between socioeconomic status (SES) and demographic markers and leukocyte telomere length (LTL) in Brazilian adults. This cross-sectional study was conducted in a subsample (women=228; men=200) nested within the Pro-Saúde study, a prospective cohort study of university civil servants in Rio de Janeiro, Brazil (2012-2013). Adjusted multivariate models were used to test the relationship between SES markers (marital status, educational attainment, father's educational attainment, race/skin color, household income, and childhood experience of food deprivation) and LTL. After adjusting for age and potential health-related confounders, lower educational attainment was associated with shorter LTL among men (β=-0.05, 95% confidence interval (CI)=95%CI: -0.10, 0.00, P=0.03). In women, LTL was inversely associated with unmarried status (β=-0.05, 95%CI: -0.09, 0.00, P=0.03), lower father's educational attainment (β=-0.05, 95%CI: -0.13, 0.00, P=0.04), and childhood experience of food deprivation (β=-0.07, 95%CI: -0.13, 0.00, P=0.04). Our findings suggested that the association between SES markers and LTL differs according to sex. SES markers able to induce lifelong stress, reflected in LTL, appeared to be more related to individual factors in men, whereas in women they were family-related.

Moderate levels of physical fitness maintain telomere length in non-senescent T CD8+ cells of aged men

OBJECTIVES: Immunosenescence is an age-associated change characterized by a decreased immune response. Although physical activity has been described as fundamental for maintaining the quality of life, few studies have evaluated the effects of different levels of exercise on telomere length in aged populations. The present study aimed to analyze the effects of different levels of physical activity, classified by the Maximal oxygen consumption (VO2 max) values, on the telomere length of memory Cluster of differentiation (CD) CD4+(CD45ROneg and CD45RO+), effector CD8+CD28neg, and CD8+CD28+ T cells in aged individuals. METHODS: Fifty-three healthy elderly men (aged 65-85 years) were included in this study. Their fitness level was classified according to the American College of Sports Medicine (ACSM) for VO2 max (mL/kg/min). Blood samples were obtained from all participants to analyze the percentage of CD3, CD4, CD8, CD28+, naïve, and subpopulations of memory T cells by using flow cytometry. Furthermore, using the Flow-FISH methodology, the CD4+CD45RO+, CD4+CD45ROneg, CD8+CD28+, and CD8+CD28negT cell telomere lengths were measured. RESULTS: There was a greater proportion of effector memory T CD4+ cells and longer telomeres in CD8+CD28+ T cells in the moderate physical fitness group than in the other groups. There was a higher proportion of terminally differentiated memory effector T cells in the low physical fitness group. CONCLUSION: A moderate physical activity may positively influence the telomere shortening of CD28+CD8+T cells. However, additional studies are necessary to evaluate the importance of this finding with regard to immune function responses in older men.

Oxidative stress, telomere length, and frailty in an old age population

Abstract Background A global aging population requires focusing on the risk factors for unhealthy aging, preventive medicine, and chronic disease management. The identification of adverse health outcomes in older adults has been addressed by the characterization of frailty as a biological syndrome. In this field, oxidative stress and telomere length have been suggested as biomarkers of aging Objective The objective of the study was to study the association of oxidative stress, telomere length, and frailty in an old age population Methods We conducted a cross-sectional study based on 2015 data from 202 members of a cohort of older adults (n = 202; F/M gender ratio: 133/69; mean age: 69.89 ± 7.39 years). Reactive oxygen species were measured by dichlorofluorescein diacetate and lipid peroxidation by malondialdehyde. Telomere length was determined using quantitative polymerase chain reaction with SYBR Green Master Mix Results Statistical analysis showed an association between telomere length and frailty but no association between oxidative stress and telomere length or frailty Conclusions Telomere length could eventually be used as a marker to differentiate between healthy and unhealthy aging as expressed by frailty phenotype; oxidative stress seemed merely a biological process of aging.

Telomere length and childhood trauma in Colombians with depressive symptoms

Objective: Childhood trauma and telomere length (TL) are important risk factors for major depressive disorder. We examined whether there was an association between childhood trauma and TL in a sample of Colombians who were assessed for depressive symptoms. Methods: We applied the Center for Epidemiologic Studies Depression scale, the Patient Health Questionnaire-9, the Hospital Anxiety and Depression scale and the Childhood Trauma Questionnaire to 92 Colombian subjects (mean age = 21). TL was measured with quantitative PCR. Spearman's correlation coefficient (rs) was used to analyze the relationship between childhood trauma scores and TL. Results: We found a significant correlation between TL and sexual abuse scores (rs = 0.428, p = 0.002) in individuals with higher depressive symptom scores. Conclusion: This is the first report of a significant association between TL and sexual abuse in a Latin American sample and provides additional evidence about the role of childhood trauma and TL in neuropsychiatric disorders.

Relationship between Telomere Maintenance and Liver Disease

Previous studies have established a correlation between increasing chronological age and risk of cirrhosis. This pattern raised interest in the role of telomeres and the telomerase complex in the pathogenesis of liver fibrosis and cirrhosis. This review aims to summarize and analyze the current understanding of telomere regulation in hepatocytes and lymphocytes and how this ultimately relates to the development of liver fibrosis. Notably, in chronic viral hepatitis, telomere shortening in hepatocytes and lymphocytes occurs in such a way that may promote further viral replication while also leading to liver damage. However, while telomere shortening occurs in both hepatocytes and lymphocytes and ultimately results in cellular death, the mechanisms of telomere loss appear to be initiated by independent processes. The understanding of telomere maintenance on a hepatic and immune system level in both viral and non-viral etiologies of cirrhosis may open doors to novel therapeutic strategies.

Telomere Biology in Mood Disorders: An Updated, Comprehensive Review of the Literature

Major psychiatric disorders are linked to early mortality and patients afflicted with these ailments demonstrate an increased risk of developing physical diseases that are characteristically seen in the elderly. Psychiatric conditions like major depressive disorder, bipolar disorder and schizophrenia may be associated with accelerated cellular aging, indicated by shortened leukocyte telomere length (LTL), which could underlie this connection. Telomere shortening occurs with repeated cell division and is reflective of a cell’s mitotic history. It is also influenced by cumulative exposure to inflammation and oxidative stress as well as the availability of telomerase, the telomere-lengthening enzyme. Precariously short telomeres can cause cells to undergo senescence, apoptosis or genomic instability; shorter LTL correlates with compromised general health and foretells mortality. Important data specify that LTL may be reduced in principal psychiatric illnesses, possibly in proportion to exposure to the ailment. Telomerase, as measured in peripheral blood monocytes, has been less well characterized in psychiatric illnesses, but a role in mood disorder has been suggested by preclinical and clinical studies. In this manuscript, the most recent studies on LTL and telomerase activity in mood disorders are comprehensively reviewed, potential mediators are discussed, and future directions are suggested. An enhanced comprehension of cellular aging in psychiatric illnesses could lead to their re-conceptualizing as systemic ailments with manifestations both inside and outside the brain. At the same time this paradigm shift could identify new treatment targets, helpful in bringing about lasting cures to innumerable sufferers across the globe.

The risk of preschool asthma at 2–4 years is not associated with leukocyte telomere length at birth or at 1 year of age

BACKGROUND: Exposure to prenatal stress is associated with offspring allergic-disease development, and oxidative stress may mediate this relationship. OBJECTIVE: We aimed to evaluate whether leukocyte telomere length (LTL) shortening, a marker for exposure to oxidative stress, in early life is associated with increased risk of asthma development during the preschool period. METHODS: We assessed the follow-up clinical data of a subgroup from a birth cohort whose LTLs had been measured from cord-blood and 1-year peripheral-blood samples. We examined whether the LTLs would be associated with asthma development at the age of 2–4 years. RESULTS: The data of 84 subjects were analyzed. LTLs were measured from the cord-blood and 1-year peripheral blood of 75 and 79 subjects, respectively. Among them, 14 subjects (16.7%) developed bronchial asthma between 2–4 years old. Prenatally stressed subjects had marginally increased odds of developing asthma (p = 0.097). There was no significant difference in the odds of preschool-asthma development between the groups with shorter and longer cord-blood LTLs (odds ratio [OR], 0.651; 95% confidence interval [CI], 0.184–2.306) or in the odds between the groups with shorter and longer 1-year peripheral-blood LTLs (OR, 0.448; 95% CI, 0.135–1.483). Finally, subjects with both higher prenatal stress and shorter LTLs did not have significantly higher odds of preschool-asthma development (for cord-blood: OR, 1.242; 95% CI, 0.353–4.368; for 1-year peripheral-blood: OR, 1.451; 95% CI, 0.428–4.919). CONCLUSION: There was no significant association between early life LTLs and higher risk of bronchial-asthma development during the preschool years.

Walnut phenolic extracts reduce telomere length and telomerase activity in a colon cancer stem cell model

BACKGROUND/OBJECTIVES: Telomeres are located at the chromosomal ends and progressively shortened during each cell cycle. Telomerase, which is regulated by hTERT and c-MYC, maintains telomeric DNA sequences. Especially, telomerase is active in cancer and stem cells to maintain telomere length for replicative immortality. Recently we reported that walnut phenolic extract (WPE) can reduce cell viability in a colon cancer stem cell (CSC) model. We, therefore, investigated the effect of WPE on telomere maintenance in the same model. MATERIALS/METHODS: CD133+CD44+ cells from HCT116, a human colon cancer cell line, were sorted by Fluorescence-activated cell sorting (FACS) and treated with WPE at the concentrations of 0, 10, 20, and 40 µg/mL for 6 days. Telomere lengths were assessed by quantitative real-time PCR (qRT-PCR) using telomere specific primers and DNA extracted from the cells, which was further adjusted with single-copy gene and reference DNA (ddCt ). Telomerase activity was also measured by qRT-PCR after incubating the PCR mixture with cell protein extracts, which was adjusted with reference DNA (dCt ). Transcriptions of hTERT and c-MYC were determined using conventional RT-PCR. RESULTS: Telomere length of WPE-treated cells was significantly decreased in a dose-dependent manner (5.16 ± 0.13 at 0 µg/mL, 4.79 ± 0.12 at 10 µg/mL, 3.24 ± 0.08 at 20 µg/mL and 3.99 ± 0.09 at 40 µg/mL; P = 0.0276). Telomerase activities concurrently decreased with telomere length (1.47 ± 0.04, 1.09 ± 0.01, 0.76 ± 0.08, and 0.88 ± 0.06; P = 0.0067). There was a positive correlation between telomere length and telomerase activity (r = 0.9090; P < 0.0001). Transcriptions of both hTERT and c-MYC were also significantly decreased in the same manner. CONCLUSIONS: In the present cell culture model, WPE reduced telomere maintenance, which may provide a mechanistic link to the effect of walnuts on the viability of colon CSCs.

Initiation of human parturition: signaling from senescent fetal tissues via extracellular vesicle mediated paracrine mechanism

A better understanding of the underlying mechanisms by which signals from the fetus initiate human parturition is required. Our recent findings support the core hypothesis that oxidative stress (OS) and cellular senescence of the fetal membranes (amnion and chorion) trigger human parturition. Fetal membrane cell senescence at term is a natural physiological response to OS that occurs as a result of increased metabolic demands by the maturing fetus. Fetal membrane senescence is affected by the activation of the p38 mitogen activated kinase-mediated pathway. Similarly, various risk factors of preterm labor and premature rupture of the membranes also cause OS-induced senescence. Data suggest that fetal cell senescence causes inflammatory senescence-associated secretory phenotype (SASP) release. Besides SASP, high mobility group box 1 and cell-free fetal telomere fragments translocate from the nucleus to the cytosol in senescent cells, where they represent damage-associated molecular pattern markers (DAMPs). In fetal membranes, both SASPs and DAMPs augment fetal cell senescence and an associated ‘sterile’ inflammatory reaction. In senescent cells, DAMPs are encapsulated in extracellular vesicles, specifically exosomes, which are 30–150 nm particles, and propagated to distant sites. Exosomes traffic from the fetus to the maternal side and cause labor-associated inflammatory changes in maternal uterine tissues. Thus, fetal membrane senescence and the inflammation generated from this process functions as a paracrine signaling system during parturition. A better understanding of the premature activation of these signals can provide insights into the mechanisms by which fetal signals initiate preterm parturition.

Leukocyte Telomere Length Reflects Prenatal Stress Exposure, But Does Not Predict Atopic Dermatitis Development at 1 Year

PURPOSE: Prenatal maternal stress affects offspring's atopic dermatitis (AD) development, which is thought to be mediated by the oxidative stress. We aimed to evaluate the difference in leukocyte telomere length (LTL), a marker for exposure to oxidative stress, according to the prenatal stress exposure and the later AD development. METHODS: From a birth cohort (the COhort for Childhood Origin of Asthma and allergic diseases) that had displayed a good epidemiologic association between the exposure to prenatal stress and AD development in the offspring, we selected 68 pairs of samples from 4 subject groups based on the level of prenatal maternal stress and later AD development. The LTL was measured from both cord blood and 1-year peripheral blood, and their LTLs were compared between subject groups. Finally, the proportion of AD development was examined in the subject groups that are reclassified based on subjects' exposure to prenatal stress and there LTL. RESULTS: Cord-blood LTL was shorter in prenatally stressed infants than in unstressed ones (P = 0.026), which difference was still significant when subjects became 1 year old (P = 0.008). LTL of cord blood, as well as one of the 1-year peripheral blood, was not different according to later AD development at 1 year (P = 0.915 and 0.174, respectively). Shorter LTL made no increase in the proportion of later AD development in either prenatally high-stressed or low-stressed groups (P = 1.000 and 0.473, respectively). CONCLUSIONS: Cord-blood LTL may reflect subjects' exposure to maternal prenatal stress. However, the LTL shortening is not a risk factor of increasing AD development until the age of 1, and a longer investigation may be necessary for validation. Currently, the results doubt the role of LTL shortening as a marker for risk assessment tool for the prenatal stress associated with AD development in the offspring.