Reduced fetal telomere length in gestational diabetes

Robust evidence supports a causal link between higher birthweight and longer telomere length: a mendelian randomization study

Background

Observational studies have suggested a potential relationship between birthweight and telomere length. However, the causal link between these two parameters remains undefined. In this study, we use Mendelian Randomization (MR). This method employs genetic variants as instrumental variables, to explore the existence of causal associations and elucidate the causal relationship between birth weight and telomere length.

Methods

We used 35 single nucleotide polymorphisms (SNPs) as instrumental variables for birth weight. These SNPs were identified from a meta-analysis involving 153,781 individuals. Furthermore, we obtained summary statistics for telomere length from a study conducted on 472,174 United Kingdom Biobank participants. To evaluate the causal estimates, we applied the random effect inverse variance weighted method (IVW) and several other MR methods, such as MR-Egger, weighted median, and MR-PRESSO, to verify the reliability of our findings.

Results

Our analysis supports a significant causal relationship between genetically predicted birth weight and telomer3e length. The inverse variance weighted analysis results for birth weight (Beta = 0.048; 95%CI = 0.023 to 0.073; p < 0.001) corroborate this association.

Conclusion

Our study provides robust evidence supporting a causal link between higher birth weight and longer telomere length.

Telomere Length in Patients with Gestational Diabetes Mellitus and Normoglycemic Pregnant Women: a Systematic Review and Meta-analysis

We performed a systematic review and meta-analysis of studies assessing telomere length in blood leukocytes or mononuclear cells in women with gestational diabetes mellitus (GDM) and normoglycemic pregnant women (NPW) and their infants. The review protocol was registered in PROSPERO (CRD42022300950). Searches were conducted in PubMed, Embase, LILACS, CNKI, and Wang Fang, from inception through November 2022. The primary outcomes were maternal and offspring telomere length. The Newcastle-Ottawa Scale was used to assess the quality of included studies. Random-effect meta-analyses were applied to estimate standardized mean differences (SMDs) and their 95% confidence interval (CI). The meta-analysis of four studies showed no significant maternal telomere length difference (SMD = -0.80, 95% CI: -1.66, 0.05) in women with GDM compared to NPW. In the sensibility analysis omitting one study with a small sample of women, the telomere length becomes significantly reduced in women with GDM (SMD = -1.10, 95% CI: -2.18, -0.02). GDM patients had increased glucose (SMD = 0.28, 95% CI: 0.09, 0.46) and glycosylated hemoglobin than NPW (SMD = 0.62, 95% CI: 0.23, 1.01) while total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides did not display differences between women with and without GDM. There was no significant difference in cord blood telomere length in offspring from women with GDM and NPW (SMD = 0.11, 95% CI: -0.52, 0.30). Cord blood insulin levels (SMD = 0.59, 95% CI: 0.33, 0.85) and birthweight (SMD = 0.59, 95% CI: 0.39, 0.79) were higher in offspring from pregnant women with GDM than in those from NPW. There were no significant differences in maternal and offspring telomere length between pregnancies with and without GDM.

Preterm Birth and Its Association with Maternal Diet, and Placental and Neonatal Telomere Length

Preterm birth (PTB), a multi-causal syndrome, is one of the global epidemics. Maternal nutrition, but also neonatal and placental telomere length (TL), are among the factors affecting PTB risk. However, the exact relationship between these factors and the PTB outcome, remains obscure. The aim of this review was to investigate the association between PTB, maternal nutrition, and placental-infant TL. Observational studies were sought with the keywords: maternal nutrition, placental TL, newborn, TL, and PTB. No studies were found that included all of the keywords simultaneously, and thus, the keywords were searched in dyads, to reach assumptive conclusions. The findings show that maternal nutrition affects PTB risk, through its influence on maternal TL. On the other hand, maternal TL independently affects PTB risk, and at the same time PTB is a major determinant of offspring TL regulation. The strength of the associations, and the extent of the influence from covariates, remains to be elucidated in future research. Furthermore, the question of whether maternal TL is simply a biomarker of maternal nutritional status and PTB risk, or a causative factor of PTB, to date, remains to be answered.

Associations of self-reported sleep duration and sleep quality during pregnancy with newborn telomere length

BACKGROUND

Telomere length (TL) at birth is considered a potential biomarker for lifelong health. Although maternal sleep disturbance has been linked to a series of adverse pregnancy outcomes, evidence on the effect of maternal sleep on newborn TL remains scarce. Therefore, we aim to investigate the association of maternal sleep duration and sleep quality with newborn TL.

METHODS

A total of 742 mother-newborn pairs were recruited from Wuhan Children's Hospital between November 2013 and March 2015. Cord blood TL was measured using real-time quantitative polymerase chain reaction. Maternal sleep duration and quality during late pregnancy were obtained via questionnaires. Multivariate linear regression models were used to estimate the effects of maternal sleep duration and sleep quality on newborn TL.

RESULTS

A total of 742 maternal-newborn pairs were included in the analyses. Mothers sleeping ≥10 hours had a 9.30% (95% CI: 2.09%, 15.99%) shorter newborn TL than those sleeping 7-<9 hours. However, the association in mothers with short sleep duration (<7 hours) did not reach statistical significance. Compared to mothers with good sleep quality, those with poor sleep quality had a 9.91% (95% CI: 4.06%, 15.40%) shorter newborn TL. We observed a joint effect of sleep duration and sleep quality on newborn telomere shortening. Women with sleep duration ≥10 hours and poor sleep quality were most likely to have newborns with short TL (percent change:-19.66%, 95% CI: -28.42, -9.84%).

CONCLUSIONS

Long sleep duration and poor sleep quality during late pregnancy were associated with shorter newborn TL.

Molecular mechanisms involved in fetal programming and disease origin in adulthood

Fetal programming occurs during the gestational age when exposure to environmental stimuli can cause long-term changes in the fetus, predisposing it to develop chronic non-communicable diseases (CNCD) in adulthood. Herein, we summarized the role of low-calorie or high-fat diets during pregnancy as fetal programming agents that induce intrauterine growth restriction (IUGR), amplified de novo lipogenesis, and increased amino acid transport to the placenta, which favor the CNCD onset in the offspring. We also outlined how maternal obesity and gestational diabetes act as fetal programming stimuli by reducing iron absorption and oxygen transport to the fetus, stimulating inflammatory pathways that boost neurological disorders and CNCD in the progeny. Moreover, we reviewed the mechanisms through which fetal hypoxia elevates the offspring's risk of developing hypertension and chronic kidney disease in adult life by unbalancing the renin-angiotensin system and promoting kidney cell apoptosis. Finally, we examined how inadequate vitamin B12 and folic acid consumption during pregnancy programs the fetus to greater adiposity, insulin resistance, and glucose intolerance in adulthood. A better understanding of the fetal programming mechanisms may help us reduce the onset of insulin resistance, glucose intolerance, dyslipidemia, obesity, hypertension, diabetes mellitus, and other CNCD in the offspring during adulthood.

Placental and Umbilical Cord Blood Oxidative Stress Level and Telomere Homeostasis in Early Onset Severe Preeclampsia

OBJECTIVE

Although the etiopathogenesis of preeclampsia (PE) is unknown, evidence suggests that it may be associated with increased oxidative stress. Studies have shown that oxidative stress can affect DNA fragments called telomeres. However, the interactions of PE, oxidative stress, and telomere length are not clearly known. This study aims to evaluate the oxidative/anti-oxidative stress balance in the placenta and umbilical cord and examine the effect of oxidative stress on telomeres.

MATERIALS-METHOD

Cord blood and placental samples were collected from 27 pregnant women with severe PE (28^0/7-33^6/7 gestational weeks) and 53 healthy pregnant women. Telomere length (TL) was measured by real-time PCR in the cord blood and placenta tissue. Total antioxidant status (TAS) and total oxidant status (TOS) levels were measured in the cord blood and placenta tissue using a colorimetric method.

RESULTS

No significant differences were found between groups regarding age, BMI, gravida, parity, and newborn gender (p>0.05). Cord blood and placental TL of PE patients were significantly shorter than the control group, while cord blood and placental TAS and TOS levels were higher (p<0.05). The results of a multivariate logistic regression analysis showed that the level of placental TOS in PE patients (OR=1.212, 95% CI=1.068-1.375) was an independent risk factor affecting PE.

CONCLUSION

This study found that oxidative stress is an independent risk factor in the development of PE and shortens TL in both placental and umbilical cord blood. Future research on telomere homeostasis may offer a new perspective for the treatment of PE.

Cellular senescence in normal and adverse pregnancy

Cellular senescence (CS) is defined as a state of terminal proliferation arrest accompanied by morphological alterations, pro-inflammatory phenotype, and metabolic changes. In recent years, the implications of senescence in numerous physiological and pathological conditions such as development, tissue repair, aging, or cancer have been evident. Some inductors of senescence are tissue repair pathways, telomere shortening, DNA damage, degenerative disorders, and wound healing. Lately, it has been demonstrated that CS plays a decisive role in the development and progression of healthy pregnancy and labor. Premature maternal-fetal tissues senescence (placenta, choriamniotic membranes, and endothelium) is implicated in many adverse pregnancy outcomes, including fetal growth restriction, preeclampsia, preterm birth, and intrauterine fetal death. Here we discuss cellular senescence and its association with normal pregnancy development and adverse pregnancy outcomes. Current evidence allows us to establish the relevance of CS in processes associated with the appropriate development of placentation, the progression of pregnancy, and the onset of labor; likewise, it allows us to understand the undeniable participation of CS deregulation in pathological processes associated with pregnancy.

Associations of cord blood leukocyte telomere length with adiposity growth from infancy to adolescence

OBJECTIVE

Leukocyte telomere length (LTL) may be a biomarker for chronic disease susceptibility, but no work has tested this hypothesis directly. Our study investigated associations of LTL at birth with markers of adiposity growth that are linked with cardiometabolic health later in life.

METHODS

Participants were 375 children in Project Viva (48% female, 71% White). Body mass index (BMI) trajectories from birth to 18 years were tracked using repeated measures of BMI collected in physical examinations and via medical records, then used to predict age (months) and magnitude (kg/m2 ) of BMI peak and rebound. LTL was measured from cord blood via duplex quantitative PCR. A binary variable indicating LTL shorter than the reference population average was the primary exposure.

RESULTS

LTL was unrelated to BMI at peak or rebound, but associations were apparent with the timing of BMI growth milestones. Short LTL was related to a later age of peak for females (β = 0.99, 95% CI = 0.16, 1.82; psex interaction  = 0.015) and an earlier age of rebound for both males and females (βcombined  = -5.26, 95% CI = -9.44, -1.08).

CONCLUSION

LTL at birth may be an early biomarker of altered adiposity growth. Newborn telomere biology may shed new insight into the developmental origins of health and disease.

Longitudinal Association of Telomere Dynamics with Obesity and Metabolic Disorders in Young Children

In adults, short leukocyte telomere length (LTL) is associated with metabolic disorders, such as obesity and diabetes mellitus type 2. These associations could stem from early life interactions between LTL and metabolic disorders. To test this hypothesis, we explored the associations between LTL and metabolic parameters as well as their evolution over time in children with or without obesity at baseline. Seventy-three (n = 73) children attending our Outpatient Clinic for the Prevention and Management of Overweight and Obesity in Childhood and Adolescence, aged 2-10 years (mean ± SD: 7.6 ± 2.0 years), were followed for 2 to 4 years. Anthropometric, clinical, and biological (including LTL by Southern blot) measurements were performed annually. Baseline LTL correlated negatively with BMI (p = 0.02), fat percentage (p = 0.01), and blood glucose (p = 0.0007). These associations persisted after adjustments for age and sex. No associations were found between LTL attrition during the follow-up period and any of the metabolic parameters. In young children, obesity and metabolic disturbances were associated with shorter telomeres but were not associated with more pronounced LTL attrition. These results suggest that short telomeres contribute to the development of obesity and metabolic disorders very early in life, which can have a major impact on health.

Variability in newborn telomere length is explained by inheritance and intrauterine environment

BACKGROUND

Telomere length (TL) and its attrition are important indicators of physiological stress and biological aging and hence may vary among individuals of the same age. This variation is apparent even in newborns, suggesting potential effects of parental factors and the intrauterine environment on TL of the growing fetus.

METHODS

Average relative TLs of newborns (cord tissue, N = 950) and mothers (buffy coat collected at 26-28 weeks of gestation, N = 892) were measured in a birth cohort. This study provides a comprehensive analysis of the effects of heritable factors, socioeconomic status, and in utero exposures linked with maternal nutrition, cardiometabolic health, and mental well-being on the newborn TL. The association between maternal TL and antenatal maternal health was also studied.

RESULTS

Longer maternal TL (β = 0.14, P = 1.99E-05) and higher paternal age (β = 0.10, P = 3.73E-03) were positively associated with newborn TL. Genome-wide association studies on newborn and maternal TLs identified 6 genetic variants in a strong linkage disequilibrium on chromosome 3q26.2 (Tag SNP-LRRC34-rs10936600: P_meta = 5.95E-08). Mothers with higher anxiety scores, elevated fasting blood glucose, lower plasma insulin-like growth factor-binding protein 3 and vitamin B12 levels, and active smoking status during pregnancy showed a higher risk of giving birth to offspring with shorter TL. There were sex-related differences in the factors explaining newborn TL variation. Variation in female newborn TL was best explained by maternal TL, mental health, and plasma vitamin B12 levels, while that in male newborn TL was best explained by paternal age, maternal education, and metabolic health. Mother's TL was associated with her own metabolic health and nutrient status, which may have transgenerational effects on offspring TL.

CONCLUSIONS

Our findings provide a comprehensive understanding of the heritable and environmental factors and their relative contributions to the initial setting of TL and programing of longevity in early life. This study provides valuable insights for preventing in utero telomere attrition by improving the antenatal health of mothers via targeting the modifiable factors.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT01174875. Registered on 1 July 2010.

Prenatal exposure to maternal psychological distress and telomere length in childhood

Telomere length (TL) is a biological marker of cellular aging, and shorter TL in adulthood is associated with increased morbidity and mortality risk. It is likely that these differences in TL are established long before adulthood, and there is growing evidence that TL can reflect prenatal experiences. Although maternal prenatal distress predicts newborn TL, it is unknown whether the relation between prenatal exposure to maternal distress and child TL persists through childhood. The purpose of the current longitudinal, prospective study is to examine the relation between prenatal exposure to maternal distress (perceived stress, depressive symptoms, pregnancy-related anxiety) and TL in childhood. Participants included 102 children (54 girls) and their mothers. Mothers' distress was assessed five times during pregnancy, at 12 weeks postpartum, and at the time of child telomere measurement between 6 and 16 years of age. Maternal distress during pregnancy predicted shorter offspring TL in childhood, even after accounting for postnatal exposure to maternal distress and other covariates. These findings indicate that maternal mental health predicts offspring TL biology later in childhood than previously observed. This study bolsters claims that telomere biology is subject to fetal programming and highlights the importance of supporting maternal mental health during pregnancy.

Maternal opioid use is reflected on leukocyte telomere length of male newborns

Opioid use accelerates normal aging in adults that raises a question on whether it may trans-generationally affect aging and aging biomarkers in the offspring of users as well? In the present research, we investigated the relative telomere length in umbilical cord blood of newborns born to opioid consuming mothers compared to normal controls. Telomere length shortening is a known biomarker of aging and aging related diseases. Its measure at birth or early in life is considered as a predictor of individual health in adulthood. Here, we performed a case-control study to investigate whether maternal opioid use affects newborns relative telomere length (RTL). 57 mother-newborn dyads were included in this study, 30 neonates with opioid using mothers (OM), and 27 with not-opioid using mothers (NOM)). RTL was measured in leukocyte cells genomic DNA using real-time PCR. The correlation of maternal opioid use with neonates telomer length was assessed using logistic regression analysis. The results displayed a significant association between odds ratio of long RTL and maternal opioid use when sensitivity analysis was performed by neonate sex; where the data indicates significantly increased odds ratio of long leukocyte RTL in association with maternal opioid use in male neonates only. Further work is necessary to assess this association in larger samples and test the potential underlying mechanisms for this observation.

Dysregulated non-coding telomerase RNA component and associated exonuclease XRN1 in leucocytes from women developing preeclampsia-possible link to enhanced senescence

Senescence in placenta/fetal membranes is a normal phenomenon linked to term parturition. However, excessive senescence which may be induced by telomere attrition, has been associated with preeclampsia (PE). We hypothesized that the telomerase complex in peripheral blood mononuclear cells (PBMC) and circulating telomere associated senescence markers would be dysregulated in women with PE. We measured long non-coding (nc) RNA telomerase RNA component (TERC) and RNAs involved in the maturation of TERC in PBMC, and the expression of TERC and 5′–3′ Exoribonuclease 1 (XRN1) in extracellular vesicles at 22–24 weeks, 36–38 weeks and, 5-year follow-up in controls and PE. We also measured telomere length at 22–24 weeks and 5-year follow-up. The circulating senescence markers cathelicidin antimicrobial peptide (CAMP), β-galactosidase, stathmin 1 (STMN1) and chitotriosidase/CHIT1 were measured at 14–16, 22–24, 36–38 weeks and at 5-year follow-up in the STORK study and before delivery and 6 months post-partum in the ACUTE PE study. We found decreased expression of TERC in PBMC early in pregnant women who subsequently developed PE. XRN1 involved in the maturation of TERC was also reduced in pregnancy and 5-year follow-up. Further, we found that the senescence markers CAMP and β-galactosidase were increased in PE pregnancies, and CAMP remained higher at 5-year follow-up. β-galactosidase was associated with atherogenic lipid ratios during pregnancy and at 5-year follow-up, in PE particularly. This study suggests a potential involvement of dysfunctional telomerase biology in the pathophysiology of PE, which is not restricted to the placenta.

Maternal diet and offspring telomere length: a systematic review

CONTEXT

Many studies assert a negative influence of inappropriate maternal diet and nutritional status during pregnancy on offspring, not only in utero but throughout life, because of the role in the programing of noncommunicable diseases. Telomere length is a biomarker of aging, and shorter telomeres are associated with chronic disease later in life. Maternal nutrition and nutritional status may be an important determinant of offspring telomere length.

OBJECTIVE

A systematic review was conducted to determine the effect of maternal nutrition and nutritional status in pregnancy on offspring telomere length.

DATA SOURCES

This systematic review was conducted according to PRISMA guidelines. Database searches of PubMed, CINAHL, Scopus, Medline, and Web of Science were performed.

STUDY SELECTION

Included studies assessed the association between maternal nutrition (dietary intake and nutritional status) during pregnancy and offspring telomere length measured in cord blood, serum, plasma, and peripheral blood mononuclear cells.

DATA EXTRACTION

Three authors screened and determined the quality of the articles; disagreements were resolved by a fourth author. All authors compared the compiled data.

RESULTS

Seven studies were extracted and evaluated. Studies comprised a double-blind placebo-controlled trial (n = 1), prospective cohort studies (n = 5), and a cross-sectional study (n = 1). Higher circulating maternal folate and 25-hydroxyvitamin D3 concentrations, along with higher maternal dietary caffeine intakes, were associated with longer offspring telomere length, whereas higher dietary intake of carbohydrate, folate, n-3 polyunsaturated fatty acids, vitamin C, or sodium was not.

CONCLUSION

The limited but suggestive evidence highlights the need for further research to be conducted in this area, particularly longitudinal studies involving larger cohorts of pregnant women.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42019136506.

Telomere length determinants in childhood

Telomere length (TL) is a dynamic marker that reflects genetic predispositions together with the environmental conditions of an individual. It is closely related to longevity and a number of pathological conditions. Even though the extent of telomere research in children is limited compared to that of adults, there have been a substantial number of studies providing first insights into child telomere biology and determinants. Recent discoveries revealed evidence that TL is, to a great extent, determined already in childhood and that environmental conditions in adulthood have less impact than first believed. Studies have demonstrated that large inter-individual differences in TL are present among newborns and are determined by diverse factors that influence intrauterine development. The first years of child growth are associated with high cellular turnover, which results in fast shortening of telomeres. The rate of telomere loss becomes stable in early adulthood. In this review article we summarise the existing knowledge on telomere dynamics during the first years of childhood, highlighting the conditions that affect newborn TL. We also warn about the knowledge gaps that should be filled to fully understand the regulation of telomeres, in order to implement them as biomarkers for use in diagnostics or treatment.

Maternal psychosocial functioning, obstetric health history, and newborn telomere length

There is growing interest in elucidating the determinants of newborn telomere length, given its potential as a biomarker of lifetime disease risk affected by prenatal exposures. There is limited evidence that increased maternal stress during pregnancy predicts shorter newborn telomere length. However, the few studies published to date have been conducted primarily with small samples utilizing inconsistent definitions of maternal stress. Moreover, the potential influence of fetal sex as a moderator of maternal stress effects on newborn telomere length has been largely ignored despite compelling evidence of likely impact. In a prospective cohort study of pregnant women seeking routine prenatal care, we tested whether a range of maternal measures of stressor exposures, subjective feelings of stress, and mental health (depression, anxiety) were associated with newborn telomere length assessed from cord blood among 146 pregnant women and their newborn infants. We further examined whether the pattern of associations differed by infant sex. Sociodemographic and maternal and newborn health indicators were considered as potential covariates. When examined within the whole sample, none of the maternal psychosocial measures were associated with newborn telomere length. Among potential covariates, maternal history of smoking and preeclampsia in a previous pregnancy were negatively associated with newborn telomere length. In adjusted linear regression analyses that considered potential sex-specific effects, maternal depression, general anxiety, and pregnancy-specific anxiety symptoms were positively associated with newborn telomere length among males. Overall, the findings provide some evidence for an association between maternal psychosocial wellbeing in pregnancy and newborn telomere length in males, although in the opposite direction than previously reported. Maternal smoking and obstetric history prior to conception may be associated with shorter offspring telomere length.

The Prenatal Hormone Milieu in Autism Spectrum Disorder

Though the etiology of autism spectrum disorder (ASD) remains largely unknown, recent findings suggest that hormone dysregulation within the prenatal environment, in conjunction with genetic factors, may alter fetal neurodevelopment. Early emphasis has been placed on the potential role of in utero exposure to androgens, particularly testosterone, to theorize ASD as the manifestation of an "extreme male brain." The relationship between autism risk and obstetric conditions associated with inflammation and steroid dysregulation merits a much broader understanding of the in utero steroid environment and its potential influence on fetal neuroendocrine development. The exploration of hormone dysregulation in the prenatal environment and ASD development builds upon prior research publishing associations with obstetric conditions and ASD risk. The insight gained may be applied to the development of chronic adult metabolic diseases that share prenatal risk factors with ASD. Future research directions will also be discussed.

Prenatal gestational diabetes mellitus exposure and accelerated offspring DNA methylation age in early childhood

Background: We investigated the association between prenatal GDM exposure and offspring DNA methylation (DNAm) age at 3-10 years of age in the Tianjin GDM Observational Study. Methods: This study included 578 GDM and 578 non-GDM mother-child pairs. Children underwent an exam with anthropometric measurements and blood draw for DNAm analysis (Illumina 850 K array) at a median age of 5.9 years (range 3.1-10.2). DNAm age was calculated using two epigenetic clock algorithms (Horvath and Hannum). The residual resulting from regressing DNAm age on chronological age was used as a metric for age acceleration. Results: Chronological age was positively correlated with Horvath DNAm age (r = 0.53, p < 0.0001) and Hannum DNAm age (r = 0.38, p < 0.0001). Offspring age acceleration was higher in the GDM group than non-GDM group after adjustment for potential confounders (Horvath: 4.96 months higher, adjusted for sex, pre-pregnancy BMI, cell-type proportions, and technical bias, p = 0.0002; Hannum: 11.2 months higher, adjusted for cell-type proportions and technical bias, p < 0.0001). Increased offspring DNAm age acceleration was associated with increased offspring weight-for-age Z-score, BMI-for-age-Z-score, waist circumference, body fat percentage, subscapular skinfold, suprailiac skinfold, upper-arm circumference, and blood pressure; findings were stronger in the GDM group. Conclusions: We found that offspring of women with GDM exhibit accelerated epigenetic age compared to control participants, independent of other maternal factors. Epigenetic age in offspring was associated with cardiometabolic risk factors, suggesting that GDM and GDM-associated factors may have long-term effects on offspring epigenetic age and contribute to health outcomes.

Prenatal maternal stress prospectively relates to shorter child buccal cell telomere length

Prenatal exposure to stress increases risk for suboptimal child and adult mental and physical health outcomes, hypothesized to occur via fetal exposure to maternal stress hormones that alter growth and development. One proposed pathway through which stress exposure in utero could affect the offspring is by accelerating cellular aging in the form of telomere attrition. We tested this hypothesis in a cohort of 111 mother-child dyads, where mothers were assessed over 6 or more years, beginning prior to conception, and later during pregnancy, postpartum, and when the children were 3-5 years old. Adjusting for child age and concurrent maternal stress, we found that higher maternal perceived stress in the 3rd trimesters of pregnancy was predictive of shorter child buccal telomere length (bTL) (β = -0.24, p < .05), while maternal preconception and postpartum maternal stress were not associated with bTL (all p's > 0.42). These findings suggest a vulnerable time period in pregnancy when maternal stress influences offspring telomere length, suggesting the early embedding of adult disease might occur through biological aging pathways.

The metabolic syndrome in pregnancy and its association with child telomere length

AIMS/HYPOTHESIS

The aim of this study was to determine whether presence of the metabolic syndrome in pregnancy associates with child telomere length or child anthropometry (weight, BMI) and BP, measured at 10 years of age.

METHODS

The Screening for Pregnancy Endpoints study (SCOPE) was a multicentre, international prospective cohort of nulliparous pregnant women recruited from Australia, New Zealand, Ireland and the UK (N = 5628). The current analysis is a 10 year follow-up of SCOPE pregnant women and their children, from the Australian cohort. Clinical data collected at 14-16 weeks' gestation during the SCOPE study were used to diagnose the metabolic syndrome using IDF criteria. Telomere length, a biomarker of ageing, was assessed by quantitative PCR from children's saliva collected at 10 years of age.

RESULTS

In women who completed follow-up (n = 255), 20% had the metabolic syndrome in pregnancy. After adjusting for a range of confounders, children of mothers who had the metabolic syndrome in pregnancy had 14% shorter telomeres than children of mothers without the metabolic syndrome in pregnancy (mean difference -0.36 [95% CI -0.74, 0.01]). Height- and weight-for-age, and BMI z scores were similar in children of mothers who did and did not have the metabolic syndrome during pregnancy.

CONCLUSIONS/INTERPRETATION

Children of mothers who had the metabolic syndrome in pregnancy have shorter telomeres, a biomarker of accelerated ageing. These findings warrant further studies in larger cohorts of children, as well as investigations into whether telomere length measured in cord blood associates with telomere length in childhood.

Earlier maternal menarche is associated with shorter newborn telomere length

The aim of our study was to investigate the relationship between maternal age at menarche and newborn telomere length which has been linked to lifespan and many age-related diseases. There were 734 mother-newborn pairs recruited from Wuhan Children's Hospital Wuhan, Hubei Province, China. Age at menarche was self-reported and categorized into three groups (≤ 12 years, 13 years, and ≥ 14 years). Telomere length in cord blood was measured using quantitative real-time polymerase chain reaction and expressed as the ratio of telomere copy number to single-copy gene number (T/S). The mean age at menarche of 734 mothers was 13.1 (± 1.1) years and the adjusted geometric means in the T/S of newborn telomeres in the three groups were 0.693, 0.721, and 0.748 respectively. Earlier age at menarche (≤ 12 years), compared with later age at menarche ≥ 14 years, was significantly associated with 7.32% (95% CI - 13.70%, - 0.23%) shorter telomere length in offspring after adjusting for potential confounders.Conclusion: Mothers with earlier age at menarche were more likely to give birth newborn with shorter telomere length. Our study provides evidences for the effect of earlier menarche on fetal telomere programming in offspring. What is Known: • Newborn telomere length is considered an indicator of lifespan and health outcomes in later life. • The adverse effects of earlier menarche age to their offspring have been found, but its relationship with newborn telomere length has not been assessed before. What is New: • This is the first study to explore the relationship of maternal menarche age with newborn telomere length. • We provided primary evidence that earlier maternal age at menarche was associated with shorter newborn telomere length.

Maternal stress or sleep during pregnancy are not reflected on telomere length of newborns

Telomeres play an important role in maintaining chromosomal integrity. With each cell division, telomeres are shortened and leukocyte telomere length (LTL) has therefore been considered a marker for biological age. LTL is associated with various lifetime stressors and health-related outcomes. Transgenerational effects have been implicated in newborns, with maternal stress, depression, and anxiety predicting shorter telomere length at birth, possibly reflecting the intrauterine growth environment. Previous studies, with relatively small sample sizes, have reported an effect of maternal stress, BMI, and depression during pregnancy on the LTL of newborns. Here, we attempted to replicate previous findings on prenatal stress and newborn LTL in a sample of 1405 infants using a qPCR-based method. In addition, previous research has been expanded by studying the relationship between maternal sleep quality and LTL. Maternal prenatal stress, anxiety, depression, BMI, and self-reported sleep quality were evaluated with self-reported questionnaires. Despite sufficient power to detect similar or even considerably smaller effects than those previously reported in the literature, we were unable to replicate the previous correlation between maternal stress, anxiety, depression, or sleep with LTL. We discuss several possible reasons for the discrepancies between our findings and those previously described.

Telomere erosion as a placental clock: From placental pathologies to adverse pregnancy outcomes

The placenta provides nutritional and gas exchange between fetus and mother. Early in pregnancy, placental trophoblasts proliferate rapidly and invade aggressively. As pregnancy progresses, placental cells begin to age. Indeed, pregnancy itself has a tightly regulated duration, determined in large part by placental lifespan. Late in pregnancy, placental cells reach a senescent apoptotic state, activated by a number of intrinsic and extrinsic factors, including oxidative stress (OS), and DNA damage. Pregnancy complications, stillbirths and neonatal deaths have been related to OS and abnormal placental aging. Telomeres, the protective nucleoprotein structures at the ends of linear chromosomes, shorten both from cell replication and from exposure to OS. When telomeres become critically short they trigger cell cycle arrest and eventually cell death. Telomere attrition thus provide an intrinsic mechanism to explain tissue senescence and aging. Mounting evidence suggests that senescence of placental and fetal membrane cells results from telomere attrition. We review the studies that have addressed the role of telomere length (TL) in placentas from normal and complicated pregnancies, including pre-eclampsia, intrauterine growth restriction, gestational diabetes, and stillbirth. To date studies have uncovered associations between TL and a number of obstetrical complications. Future research is needed to determine whether these associations are causative, i.e. whether these clinical conditions result from telomere dysfunction, and whether particular features of telomeres, e.g. mean or shortest length, etc. could serve as clinically useful biomarkers of placental health.

Beneficial Effects of n-3 Polyunsaturated Fatty Acids on Offspring's Pancreas of Gestational Diabetes Rats

We studied the long-term influence of gestational diabetes mellitus (GDM) on the pancreas of offspring and the effect of omega-3 polyunsaturated fatty acids (n-3 PUFAs) on offspring's pancreas. GDM offspring were divided into three groups: GDM offspring, n-3 PUFA-adequate-GDM offspring, and n-3 PUFA-deficient GDM offspring. All healthy and GDM offspring were fed up to 11 months old. The pancreas of GDM offspring exhibited fatty infiltration at 11 months old, whereas n-3 PUFA improved the pancreatic fatty infiltration. n-3 PUFA lowered the pancreatic oxidative stress and inflammation. Surprisingly, n-3 PUFA postponed pancreatic telomere shortening of GDM offspring at old age. Nontargeted metabolomics showed that many metabolites were altered in the pancreas of GDM offspring at old age, including l-valine, ceramide, acylcarnitines, tocotrienol, cholesteryl acetate, and biotin. n-3 PUFA modulated some altered metabolites and metabolic pathways. Therefore, GDM caused the long-term effects on offspring's pancreas, whereas n-3 PUFA played a beneficial role.

N-3 Polyunsaturated Fatty Acids Decrease Long-Term Diabetic Risk of Offspring of Gestational Diabetes Rats by Postponing Shortening of Hepatic Telomeres and Modulating Liver Metabolism

The long-term influence of gestational diabetes mellitus (GDM) on offspring and the effect of omega-3 polyunsaturated fatty acids (n-3 PUFA) on GDM offspring are poorly understood. We studied the long-term diabetic risk in GDM offspring and evaluated the effect of n-3 PUFA intervention. Healthy offspring rats were fed standard diet (soybean oil) after weaning. GDM offspring were divided into three groups: GDM offspring (soybean oil), n-3 PUFA adequate offspring (fish oil), and n-3 PUFA deficient offspring (safflower oil), fed up to 11 months old. The diabetic risk of GDM offspring gradually increased from no change at weaning to obvious impaired glucose and insulin tolerance at 11 months old. n-3 PUFA decreased oxidative stress and inflammation in the liver of older GDM offspring. There was a differential effect of n-3 PUFA and n-6 PUFA on hepatic telomere length in GDM offspring. Non-targeted metabolomics showed that n-3 PUFA played a modulating role in the liver, in which numerous metabolites and metabolic pathways were altered when GDM offspring grew to old age. Many metabolites were related to diabetes risk, such as α-linolenic acid, palmitic acid, ceramide, oxaloacetic acid, tocotrienol, tetrahydro-11-deoxycortisol, andniacinamide. In summary, GDM offspring exhibited obvious diabetes risk at old age, whereas n-3 PUFA decreased this risk.

Leukocyte telomere length, lipid parameters and gestational diabetes risk: a case-control study in a Chinese population

Telomere length (TL) is linked to various age-related diseases, but little is known about telomeres in gestational diabetes mellitus (GDM). We surveyed 509 subjects (113 GDM patients and 396 frequency matched controls) in Nanjing Drum Tower Hospital, Jiangsu province of eastern China. Relative telomere length (RTL) of genomic DNA extracted from peripheral blood leukocytes was measured using quantitative polymerase chain reaction (qPCR). Odds ratios (OR) and 95% confidence interval (CI) of GDM risk were calculated across tertiles of RTL using logistic regression model. Lipid parameters during the third trimesters of gestation (after 32 weeks) were collected from medical records. The general linear correlation test was used to explore the associations of lipid parameters with RTL. Our results showed that the RTL in GDM patients were significantly shorter than controls (0.302 ± 0.112 vs. 0.336 ± 0.164, P = 0.046). However, the GDM risk was significantly increased in subjects with median RTL (adjusted OR [aOR]: 1.936, 95% CI: 1.086, 3.453, P = 0.025) and the shortest RTL (aOR: 1.795, 95% CI: 1.004, 3.207, P = 0.048), compared to subjects with longest RTL. We also demonstrated that the lipid ratios (TC/TG, LDL/TG, HDL/TG, LDL/TC, TC/LDL) were significantly associated with RTL among controls. Overall, the present study indicated that attrition of telomeres would increase GDM risk among pregnant women, and the altered lipid levels may play an important role in RTL related GDM risk and pathogenesis.

Metformin and insulin treatment prevent placental telomere attrition in boys exposed to maternal diabetes

Shortened leukocyte and placental telomeres associated with gestational diabetes mellitus (GDM) suggest this exposure triggers telomere attrition contributing to adverse outcomes. We applied high resolution Single Telomere Length Analysis (STELA) to placenta from GDM pregnancies with different treatment pathways to determine their effectiveness at preventing telomere attrition. Differences in telomere length between control (N = 69), GDM lifestyle intervention (n = 14) and GDM treated with metformin and/or insulin (n = 17) was tested by Analysis of Covariance (ANCOVA) followed by group comparisons using Fisher's least significant difference. For male placenta only, there were differences in mean telomere length (F(2,54) = 4.98, P = 0.01) and percentage of telomeres under 5 kb (F(2,54) = 4.65, P = 0.01). Telomeres were shorter in the GDM lifestyle intervention group compared to both controls (P = 0.02) and medically treated pregnancies (P = 0.003). There were more telomeres under 5 kb in the GDM lifestyle intervention group compared to the other two groups (P = 0.03 and P = 0.004). Although further work is necessary, we suggest that early adoption of targeted medical treatment of GDM pregnancies where the fetus is known to be male may be an effective strategy for ameliorating adverse outcomes for children.

Exposure to Maternal Diabetes Mellitus Causes Renal Dopamine D1 Receptor Dysfunction and Hypertension in Adult Rat Offspring

Epidemiological and experimental studies suggest that maternal diabetes mellitus programs hypertension that is associated with impaired sodium excretion in the adult offspring. However, the underlying mechanisms are not clear. Because dopamine receptor function is involved in the pathogenesis of hypertension, we hypothesized that impaired renal dopamine D1 receptor function is also involved in the hypertension in offspring of maternal diabetes mellitus. Maternal diabetes mellitus was induced by a single intraperitoneal injection of streptozotocin (35 mg/kg) to pregnant Sprague-Dawley rats at day 0 of gestation. Compared with the offspring of mothers injected with citrate buffer (control mother offspring), the diabetic mother offspring (DMO) had increased systolic blood pressure and impaired D1 receptor-mediated diuresis and natriuresis, accompanied by increased renal PKC (protein kinase C) expression and activity, GRK-2 (G protein-coupled receptor kinase-2) expression, D1 receptor phosphorylation, D1 receptor/Gαs uncoupling, and loss of D1 receptor-mediated inhibition of Na+-K+-ATPase activity in renal proximal tubule cells from DMO. Inhibition of PKC reduced the increased GRK-2 expression and normalized D1 receptor function in primary cultures of renal proximal tubule cells from DMO. In addition, DMO, relative to control mother offspring, in vivo, had increased oxidative stress, indicated by decreased renal glutathione and increased renal malondialdehyde and urine 8-isoprostane. Normalization of oxidative stress with tempol also normalized the renal D1 receptor phosphorylation, D1 receptor-mediated diuresis and natriuresis, and blood pressure in DMO. Our present study indicates that maternal diabetes mellitus-programed hypertension in the offspring is caused by impaired renal D1 receptor function because of oxidative stress that is mediated by increased PKC-GRK-2 activity.

Exposure to different intrauterine environments: implications for telomere attrition in early life

Objective: Studies focusing on telomere attrition in newborns and what factors could be involved in this issue are sparse; most reports have been in adult populations. Thereby, the aim of this study was to present an overview of what is currently known about the relationship between environmental exposure of the fetus during pregnancy and telomere length outcomes in early life. Methods: The MEDLINE (via PubMed) and Bireme databases were searched for studies published until 1 June 2016. Studies that reported telomere length measurement from birth to age 1 year were included. Results: Fifteen articles were selected that evaluated possible relationships between maternal smoking, hyperglycemia, hypertension, sleep apnea, psychological stress, folate concentration in early pregnancy, and radiation, in addition to small-for-gestational-age status and preterm birth. We found that sleep apnea, psychological stress, and folate concentration in early pregnancy were associated with telomere shortening in the newborn. No association was found with radiation, small-for-gestational-age status, or preterm birth. Results for maternal smoking, hyperglycemia, and hypertension were conflicting, and further studies should be considered. Conclusion: The actual clinical implications of these findings have yet to be investigated.

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.

The fetal programming of telomere biology hypothesis: an update

Research on mechanisms underlying fetal programming of health and disease risk has focused primarily on processes that are specific to cell types, organs or phenotypes of interest. However, the observation that developmental conditions concomitantly influence a diverse set of phenotypes, the majority of which are implicated in age-related disorders, raises the possibility that such developmental conditions may additionally exert effects via a common underlying mechanism that involves cellular/molecular ageing-related processes. In this context, we submit that telomere biology represents a process of particular interest in humans because, firstly, this system represents among the most salient antecedent cellular phenotypes for common age-related disorders; secondly, its initial (newborn) setting appears to be particularly important for its long-term effects; and thirdly, its initial setting appears to be plastic and under developmental regulation. We propose that the effects of suboptimal intrauterine conditions on the initial setting of telomere length and telomerase expression/activity capacity may be mediated by the programming actions of stress-related maternal-placental-fetal oxidative, immune, endocrine and metabolic pathways in a manner that may ultimately accelerate cellular dysfunction, ageing and disease susceptibility over the lifespan. This perspectives paper provides an overview of each of the elements underlying this hypothesis, with an emphasis on recent developments, findings and future directions.This article is part of the theme issue 'Understanding diversity in telomere dynamics'.

State of the Science: Using Telomeres as Biomarkers During the First 1,000 Days of Life

Telomere biology shows promise as an integrative biomarker of exposures and increased occurrence of chronic disease and early mortality. This integrative review examined the state of the science regarding toxicokinetic risks and maternal factors in humans and in vivo models that are correlated with telomere length during the first 1,000 days of life. The Preferred Reporting Items of Systematic Reviews and Meta-Analyses framework assisted in guiding this integrative by aiding researchers in identifying, selecting, and critically appraising the literature. Ovid MEDLINE, CINAHL, Cochrane Systematic Reviews, Web of Science, and SCOPUS databases were searched. The initial search yielded a total of 381 published articles. Full-text screening resulted in 19 articles retained for review (14 quasi-experimental studies and five experimental studies). Findings suggest a relationship between toxicokinetic exposures creating inflammation or oxidative stress (i.e., smoking) and maternal health conditions such as sleep apnea to shorter telomere length in children below 2 years old.

Fetal programming of the metabolic syndrome

Prenatal development is currently recognized as a critical period in the etiology of human diseases. This is particularly so when an unfavorable environment interacts with a genetic predisposition. The fetal programming concept suggests that maternal nutritional imbalance and metabolic disturbances may have a persistent and intergenerational effect on the health of offspring and on the risk of diseases such as obesity, diabetes, and cardiovascular diseases.

Correlation of cord blood telomere length with birth weight

Background

Intrauterine growth restriction affects 3% of newborns; and the lightest 10% of whom are classified as small for gestational age (SGA). These low-birth weight newborns are at increased risk of neonatal morbidity such as hypoxia and hypoglycaemia. In later life, they are at higher risk of several age-related diseases such as cardiovascular and metabolic disorders and dementia. As having short telomeres is also associated with these diseases, we tested if these newborns might already start with shorter telomeres at birth.

Findings

Relative telomere lengths were determined using quantitative real-time PCR in cord blood samples from 195 newborns of Chinese ancestry. Based on the telomere length normalised to a single copy gene and a reference DNA sample as internal control, we found statistically significant correlations between relative telomere length and both unadjusted and gestational age-adjusted birth weight, with the lighter newborns having shorter telomeres. The SGA birth weight group comprising the bottom 10% of the samples also had the shortest telomeres compared to the medium and heaviest birth weight groups.

Conclusions

Our results indicate that there is reduction of cord blood telomere length for newborns with lower birth weight.

The Telomeric Complex and Metabolic Disease

The attrition of telomeres is believed to be a key event not only in mammalian aging, but also in disturbed nutrient sensing, which could lead to numerous metabolic dysfunctions. The current debate focuses mainly on the question whether telomere shortening, e.g., as a heritable trait, may act as a cause or rather represents a consequence of such chronic diseases. This review discusses the damaging events that ultimately may lead or contribute to telomere shortening and can be associated with metabolic diseases.

Preterm infants have significantly longer telomeres than their term born counterparts

There are well-established morbidities associated with preterm birth including respiratory, neurocognitive and developmental disorders. However several others have recently emerged that characterise an 'aged' phenotype in the preterm infant by term-equivalent age. These include hypertension, insulin resistance and altered body fat distribution. Evidence shows that these morbidities persist into adult life, posing a significant public health concern. In this study, we measured relative telomere length in leukocytes as an indicator of biological ageing in 25 preterm infants at term equivalent age. Comparing our measurements with those from 22 preterm infants sampled at birth and from 31 term-born infants, we tested the hypothesis that by term equivalent age, preterm infants have significantly shorter telomeres (thus suggesting that they are prematurely aged). Our results demonstrate that relative telomere length is highly variable in newborn infants and is significantly negatively correlated with gestational age and birth weight in preterm infants. Further, longitudinal assessment in preterm infants who had telomere length measurements available at both birth and term age (n = 5) suggests that telomere attrition rate is negatively correlated with increasing gestational age. Contrary to our initial hypothesis however, relative telomere length was significantly shortest in the term born control group compared to both preterm groups and longest in the preterm at birth group. In addition, telomere lengths were not significantly different between preterm infants sampled at birth and those sampled at term equivalent age. These results indicate that other, as yet undetermined, factors may influence telomere length in the preterm born infant and raise the intriguing hypothesis that as preterm gestation declines, telomere attrition rate increases.

Leukocyte Telomere Length in the Neonatal Offspring of Mothers with Gestational and Pre-Gestational Diabetes

Aims

Telomeres undergo shortening with cell division, accelerated by increased oxidative stress. We aimed to demonstrate shortened telomeres in the offspring of mothers who have diabetes as a consequence of exposure to increased oxidative stress during intrauterine development.

Methods

We examined the level of glycaemia (glucose, HbA1c, fructosamine), oxidative stress (lipid peroxidation) and the levels of antioxidant enzymes (Superoxide dismutase (SOD) and Selenium dependent glutathione peroxidase) and correlate these findings with mean telomere length (TL) in maternal and foetal blood in groups of pregnant women with pre-gestational diabetes (PGD), gestational diabetes (GD) and a euglycaemic control group.

Results

Foetal and maternal glucose, maternal HbA1c, and foetal insulin and C-peptide were higher in the PGD group with the GD group being intermediate. Markers of oxidative stress did not vary between groups with the exception of foetal SOD activity that was highest in the GD group. There were no detectable differences in maternal or foetal TL between study groups. An exploratory analysis looking at correlations between glycaemic and oxidative stress parameters and TL revealed a negative correlation between maternal and foetal glucose and TL across the whole study population. This relationship held for the short-term marker of glycaemic control, fructosamine.

Conclusions

We were unable to show significant telomere shortening in the offspring of mothers with PGD or GD. Exploratory analysis revealed a relationship between foetal TL and short-term glycaemia particularly in PGD. It is possible that increased telomerase activity can compensate for long-term increased oxidative stress but not for short-term dysglycaemia.

Telomere length change plateaus at 4 years of age in Latino children: associations with baseline length and maternal change

Telomeres are the protective complexes at the end of chromosomes, required for genomic stability. Little is known about predictors of attrition in young children or the relationship between parental and child patterns of telomere change. Telomere length was assessed twice over one year, at 4 and at 5 years of age, in Latino preschool children (n = 77) and their mothers (n = 70) in whole blood leukocytes. Maternal and child rates of attrition during the same time period were compared in 70 mother-child pairs. More children showed lengthened telomeres over one year compared to their mothers and very few children showed attrition (2.6 %). Approximately 31 % of children and 16 % of mothers displayed lengthening over one year while 66 % of children showed maintenance in contrast with 74 % of mothers. The strongest predictor for child telomere length change was child's baseline telomere length (r = -0.61, p < 0.01). Maternal rate of change was associated with child rate of change (r = 0.33, p < 0.01). After controlling for child baseline telomere length, the relationship between child and maternal rate of change trended towards significance (Coeff = 0.20, 95 % CI -0.03 to 0.43; p = 0.08). We found primarily maintenance and lengthening from 4 to 5 years of age in children, with minimal telomere attrition, indicating that most of the telomere loss happens in the first 4 years, plateauing by age 4. Lastly, we found close to 10 % of the variance in rate of change in children shared by mothers. While some of this shared variance is genetic, there are likely environmental factors that need to be further identified that impact rate of telomere length change.

Cord blood telomere length in Latino infants: relation with maternal education and infant sex

OBJECTIVE

Telomere length (TL) has important consequences for early disease and lifelong health. However, few studies have examined determinants of TL at birth.

STUDY DESIGN

Here we test associations between cord blood TL and parental and birth factors associated with exposure to stress and indicative of healthy intrauterine life in Latino infants. We tested associations that were significant in bivariate analysis in a multivariate regression model to identify independent predictors for shorter TL at birth.

RESULT

Two novel and independent predictors emerged in our analysis of 54 infants. Female gender was associated with longer TL by ~350 base pairs (adjusted β-coefficient for male gender=-369.57, (95% confidence interval, -718.21 to (-)20.92), P=0.02); rho=-0.26, P=0.057). Increased maternal high-school education, as indicated by a high-school diploma or additional education beyond high school, was also associated with longer TL, by ~500 base pairs (adjusted β-coefficient for high-school diploma or greater=505.68 (95% confidence interval, 151.69 to 859.68), P<0.01); rho=0.36, P<0.01). Increasing head circumference trended towards statistical significance in association with longer TL (adjusted β-coefficient = 7.33; 95% confidence interval -0.52 to 15.18; P=0.07). When we removed all infants who had been exposed to high oxidative stress in pregnancy including those exposed to maternal hypertension, preeclampsia, gestational diabetes, and those who were low birth weight or preterm birth (n=7), increasing birth weight percentile was associated with longer TL (adjusted β-coefficient=8.04 (95% confidence interval 0.07 to 16.00), P=0.048).

CONCLUSION

Shorter TL at birth is associated with being male, low maternal education (less than a high school degree), and a trend towards lower birth weight and head circumference. Given the critical role of long TL in predicting health and disease, these findings contribute to the growing literature attempting to understand determinants of TL.

Telomere homeostasis in IUGR placentas - A review

Telomeres are nucleoprotein structures located at the termini of chromosomes. They are essential for chromosome stability. Telomeres become shorter due to mitotic cycles and environmental factors. When telomeres are shortened and therefore dysfunctional, cellular senescence occurs and organ dysfunction might develop. During pregnancy, fetal growth restriction secondary to placental insufficiency has been linked to impaired telomere homeostasis in which telomeres are shorter, telomerase is decreased, and compensatory mechanisms of telomere capture are enhanced. These characteristics, along with increased signs of senescence, indicate telomere dysfunction in trophoblasts from placentas affected by intrauterine growth restriction (IUGR). This review summarizes the information currently available regarding telomere homeostasis in trophoblasts from human pregnancies affected by IUGR. Improved understanding of placental physiology might help in the development of treatment options for fetuses with IUGR.

Setting the trajectory: racial disparities in newborn telomere length

OBJECTIVE

To explore racial differences in newborn telomere length (TL) and the effect moderation of the sex of the infant while establishing the methodology for the use of newborn blood spots for TL analyses.

STUDY DESIGN

Pregnant mothers were recruited from the Greater New Orleans area. TL was determined via monochrome multiplex quantitative real-time polymerase chain reaction on DNA extracted from infant blood spots. Demographic data and other covariates were obtained via maternal report before the infant's birth. Birth outcome data were obtained from medical records and maternal report.

RESULTS

Black infants weighed significantly less than white infants at birth and had significantly longer TL than white infants (P=.0134), with the strongest effect observed in black female infants. No significant differences in gestational age were present.

CONCLUSIONS

Significant racial differences in TL were present at birth in this sample, even after we controlled for a range of birth outcomes and demographic factors. Because longer initial TL is predictive of more rapid TL attrition across the life course, these findings provide evidence that, even at birth, biological vulnerability to early life stress may differ by race and sex.

Telomeres, early-life stress and mental illness

Telomeres are structures of tandem TTAGGG repeats that are found at the ends of chromosomes and preserve genomic DNA by serving as a disposable buffer to protect DNA termini during chromosome replication. In this process, the telomere itself shortens with each cell division and can consequently be thought of as a cellular 'clock', reflecting the age of a cell and the time until senescence. Telomere shortening and changes in the levels of telomerase, the enzyme that maintains telomeres, occur in the context of certain somatic diseases and in response to selected physical stressors. Emerging evidence indicates that telomeres shorten with exposure to psychosocial stress (including early-life stress) and perhaps in association with some psychiatric disorders. These discoveries suggest that telomere shortening might be a useful biomarker for the overall stress response of an organism to various pathogenic conditions. In this regard, telomeres and their response to both somatic and psychiatric illness could serve as a unifying stress-response biomarker that crosses the brain/body distinction that is often made in medicine. Prospective studies will help to clarify whether this biomarker has broad utility in psychiatry and medicine for the evaluation of responses to psychosocial stressors. The possibility that telomere shortening can be slowed or reversed by psychiatric and psychosocial interventions could represent an opportunity for developing novel preventative and therapeutic approaches.

The influence of the telomere-telomerase system on diabetes mellitus and its vascular complications

INTRODUCTION

The telomere-telomerase system plays an important role in the pathogenesis and disease progression of diabetes mellitus as well as in its vascular complications. Recent studies suggest that telomere shortening and abnormal telomerase activity occur in patients with diabetes mellitus, and targeting the telomere-telomerase system has become a prospective treatment for diabetes mellitus and its vascular complications. This review highlights the significance of the telomere-telomerase system and supports its role as a possible therapeutic target for patients with diabetes mellitus and its vascular complications Areas covered: This review covers the advances in understanding the telomere-telomerase system over the last 30 years and its significance in diabetes mellitus. In addition, it provides knowledge regarding the significance of the telomere-telomerase system in diabetes mellitus and its vascular complications as well as its role and mechanisms in oxidative stress, cell therapy and antioxidant activity Expert opinion: The telomere-telomerase system may be a potential therapeutic target that can protect against DNA damage and apoptosis in patients with diabetes mellitus and its vascular complications. DNA damage and apoptosis are associated with oxidative stress and are involved in the dysfunction of pancreatic β cells, insulin resistance, and its vascular complications. Abnormalities in the telomere-telomerase system may be associated with diabetes mellitus and its vascular complications. Therapies targeting telomere-telomerase system, telomerase reverse transcriptase transfection and alterative telomere lengthening must be identified before gene therapy can commence.

Epigenetic and developmental influences on the risk of obesity, diabetes, and metabolic syndrome

Metabolic syndrome is a growing cause of morbidity and mortality worldwide. Metabolic syndrome is characterized by the presence of a variety of metabolic disturbances including obesity, hyperlipidemia, hypertension, and elevated fasting blood sugar. Although the risk for metabolic syndrome has largely been attributed to adult lifestyle factors such as poor nutrition, lack of exercise, and smoking, there is now strong evidence suggesting that predisposition to the development of metabolic syndrome begins in utero. First posited by Hales and Barker in 1992, the "thrifty phenotype" hypothesis proposes that susceptibility to adult chronic diseases can occur in response to exposures in the prenatal and perinatal periods. This hypothesis has been continually supported by epidemiologic studies and studies involving animal models. In this review, we describe the structural, metabolic and epigenetic changes that occur in response to adverse intrauterine environments including prenatal and postnatal diet, maternal obesity, and pregnancy complications. Given the increasing prevalence of metabolic syndrome in both the developed and developing worlds, a greater understanding and appreciation for the role of the intrauterine environment in adult chronic disease etiology is imperative.

Leucocyte telomere length and risk of type 2 diabetes mellitus: new prospective cohort study and literature-based meta-analysis

Background

Short telomeres have been linked to various age-related diseases. We aimed to assess the association of telomere length with incident type 2 diabetes mellitus (T2DM) in prospective cohort studies.

Methods

Leucocyte relative telomere length (RTL) was measured using quantitative polymerase chain reaction in 684 participants of the prospective population-based Bruneck Study (1995 baseline), with repeat RTL measurements performed in 2005 (n = 558) and 2010 (n = 479). Hazard ratios for T2DM were calculated across quartiles of baseline RTL using Cox regression models adjusted for age, sex, body-mass index, smoking, socio-economic status, physical activity, alcohol consumption, high-density lipoprotein cholesterol, log high-sensitivity C-reactive protein, and waist-hip ratio. Separate analyses corrected hazard ratios for within-person variability using multivariate regression calibration of repeated measurements. To contextualise findings, we systematically sought PubMed, Web of Science and EMBASE for relevant articles and pooled results using random-effects meta-analysis.

Results

Over 15 years of follow-up, 44 out of 606 participants free of diabetes at baseline developed incident T2DM. The adjusted hazard ratio for T2DM comparing the bottom vs. the top quartile of baseline RTL (i.e. shortest vs. longest) was 2.00 (95% confidence interval: 0.90 to 4.49; P = 0.091), and 2.31 comparing the bottom quartile vs. the remainder (1.21 to 4.41; P = 0.011). The corresponding hazard ratios corrected for within-person RTL variability were 3.22 (1.27 to 8.14; P = 0.014) and 2.86 (1.45 to 5.65; P = 0.003). In a random-effects meta-analysis of three prospective cohort studies involving 6,991 participants and 2,011 incident T2DM events, the pooled relative risk was 1.31 (1.07 to 1.60; P = 0.010; I² = 69%).

Conclusions/Interpretation

Low RTL is independently associated with the risk of incident T2DM. To avoid regression dilution biases in observed associations of RTL with disease risk, future studies should implement methods correcting for within-person variability in RTL. The causal role of short telomeres in T2DM development remains to be determined.

The functional polymorphism rs73598374:G>A (p.Asp8Asn) of the ADA gene is associated with telomerase activity and leukocyte telomere length

Recent evidence demonstrated a relevant role of adenosine deaminase (ADA) in replicative senescence of T cells through its capacity to modulate telomerase activity (TA). Herein, we tested the impact of the functional polymorphism ADA rs73598374:G>A (c.22G>A, p.Asp8Asn) on telomere biology, by measuring TA and leukocyte telomere length (LTL) in healthy subjects selected according to rs73598374 genotype. rs73598374-A carriers showed lower TA (P=0.019) and shorter LTL (P=0.003), respectively, compared to G/G carriers. rs73598374-A carriers showed a stronger cross-sectional age reduction of LTL (r=-0.314, P=0.005) compared to G/G carriers (r=-0.243, P=0.022). The reduced ADA activity associated to rs73598374-A variant predisposes those carriers to display higher levels of adenosine compared to G/G carriers. Consequently, it may lead to an accelerated process of replicative senescence, causing a stronger reduction of TA and in turn shorter LTL. In conclusion, the crucial role played by replicative senescence of the immune system in several human diseases and in the aging process underscores the relevance of the present findings and also spurs interest into the possible involvement of rs73598374 in shaping the susceptibility to several age-related diseases.