Telomeres are shorter in placentas from pregnancies with uncontrolled diabetes

Association of early pregnancy telomere length and mitochondrial copy number with gestational diabetes mellitus and depressive symptoms

AIM

A bidirectional link exists between depression and gestational diabetes mellitus (GDM). While telomere length (TL) and mitochondrial DNA copy number (mtDNA-CN) alterations have been reported either in GDM or depression, their predictive ability of GDM with coexisting depression remains unexplored. We, therefore, prospectively investigated the relationship of TL and mtDNA-CN in blood leukocytes during early pregnancy and explored their potential as predictive biomarkers for identifying the risk of developing GDM with depressive symptoms later in pregnancy.

METHODS

A nested cohort of 301 women with normal fasting glucose and without depressive symptoms in early pregnancy (<16 weeks) were selected from the STratification of Risk of Diabetes in Early Pregnancy (STRiDE) study. At 24-28 weeks (OGTT visit), a 75 g OGTT and PHQ-9 were performed. Women were categorized into four groups: NGT without depressive symptoms (n = 80), NGT with depressive symptoms (n = 105), GDM without depressive symptoms (n = 75), and GDM with depressive symptoms (n = 41). Blood leukocyte TL and mtDNA-CN were assessed using qRT-PCR.

RESULTS

TL and mtDNA-CN at early pregnancy were lower in women with GDM, depressive symptoms or both, compared to NGT without depressive symptoms at OGTT visit. TL and mtDNA-CN at early pregnancy were negatively associated with PHQ-9 score and OGTT blood glucose levels at OGTT visit after adjusting for age, pre-pregnancy BMI and family history of diabetes. Higher levels of both TL and mtDNA-CN in early pregnancy were associated with lower adjusted Relative Risk (aRR) (TL; aRR: 0.34; 95 % CI: 0.28, 0.41, mtDNA-CN; aRR: 0.83; 95 % CI: 0.74, 0.93) of GDM with depressive symptoms at OGTT visit.

CONCLUSION

Lower levels of TL and mtDNA-CN in early pregnancy are significantly associated with the later development of GDM and depressive symptoms at OGTT visit. Our findings indicate that early trimester TL and mtDNA-CN could be potential predictive biomarkers for predicting GDM with depressive symptoms and emphasize their potential for improved risk assessment so as to adopt preventive strategies targeting these conditions.

Prenatal irisin is inversely related to the term placental telomere length

Irisin is a myokine mainly produced by skeletal muscle that impacts the body's systemic metabolism. It is connected to aging, telomere length, and oxidative stress markers in human adults and in vitro. The serum irisin concentration increases during pregnancy and has been linked to some birth outcomes like macrosomia. On the other hand, its inverse relation with the chance of pregnancy disorders like preeclampsia and gestational diabetes suggests a protective role for this myokine in pregnancy. It is suggested that irisin may exert its impact on pregnancy by affecting the placenta, which has not been studied yet. Here, we questioned whether prenatal serum irisin is related to placental markers, including telomere length and antioxidant activity. Research has shown that the status of these markers at birth can predict the predisposition to some chronic diseases later in life. We included 80 pregnant mothers (17-41 years old) and newborn dyads randomly selected from the enrolled participants of the Rafsanjan Birth Cohort Study (one of the five district areas of the PERSIAN birth cohort studies), who delivered at the Nik-Nafs Maternity Hospital in Rafsanjan in 2022. Irisin levels were measured in the mother's blood serum in pregnancy using ELISA. The relative telomere length and the GPX and SOD enzyme activities were measured in the term placenta using real-time PCR and colorimetric assays, respectively. We found an inverse relationship between the serum irisin levels during pregnancy and relative telomere length in the term placenta. Irisin level was not significantly associated with the activity of SOD and GPX enzymes. Therefore, our data does not support the protective role of prenatal irisin on the placental telomere shortening and oxidative stress. Future studies are warranted to assess more placental markers in relation to pregnancy irisin levels.

Differential activation of p53-Lamin A/C and p16-RB mediated senescence pathways in trophoblast from pregnancies complicated by type A2 Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) increases maternal risks such as hypertension and future type 2 diabetes while also contributing to fetal complications such as large-for-gestational-age infants and stillbirth. The placenta which is crucial for fetal development, exhibits structural and functional changes in GDM, but the impact of these alterations on placental trophoblast function remains unclear. During their differentiation villous cytotrophoblast display several characteristics of senescent cells however the role of senescence pathways in placental function remains unexplored in GDM. Here we investigate whether placental senescence pathways are altered in GDM, utilizing term villous tissue and primary trophoblasts to assess molecular changes, and determined fetal sex-based differences. Our data suggest that both p21 and p16 mediated senescence pathways are activated during trophoblast differentiation and are dysregulated in GDM placenta in a sexually dimorphic manner. We also provide evidence for increased activation of p53-Lamin A/C and p16-RB pathways in trophoblast from GDM placentas. Reduced expression of p21 and its downstream effects on GCM1 expression and βhCG secretion outline how altered physiological senescence can affect trophoblast differentiation and function. This is a seminal study highlighting how placental senescence pathways are altered in pregnancies complicated by GDM.

ARID1A recruits GATA2 to regulate the senescence of trophoblast cells under high-glucose condition

INTRODUCTION

Gestational diabetes mellitus (GDM) is a common complication during pregnancy. The hyperglycemic stimulation of gestational diabetes inhibits the invasion of the placental trophoblast cells. Some studies have indicated that the senescence of trophoblast cells weakens their invasive capacity, while the mechanism of trophoblast cells senescence in GDM remain elusive.

METHODS

We performed western blotting and Immunohistochemical staining to investigate AT-Rich Interaction Domain 1A (ARID1A) expression in GDM placental tissues. 5 mM and 30 mM glucose treated HTR-8/SVneo cells to simulate normal glucose (NG) stress and high glucose (HG) stress. Cell proliferation capacity was investigated by CCK8 assay and cell cycle assay. SA-β-gal was used to detect cellular senescence. Chip-seq characterized the binding site of ARID1A to CDKN1A. In conjunction with bioinformatics analysis, co-immunoprecipitation assays, Chip-qPCR and luciferase reporter assays were performed to prove ARID1A recruits GATA2 to CDKN1A.

RESULTS

We found that ARID1A has a higher expression levels in GDM placental tissues compared to the control. ARID1A overexpression suppressed cell proliferation, induced cell cycle arrest and promoted cell senescence. Conversely the inhibition of ARID1A significantly rescues HG induced senescence of trophoblast cells. To further characterize the mechanism by which ARID1A regulate the transcription of CDKN1A, co-immunoprecipitation assays, Chip-qPCR and luciferase reporter assay indicate that ARID1A recruits GATA2 to regulate the transcriptional activity of CDKN1A.

DISCUSSION

Our study uncovers a ARID1A mediated regulatory mechanism in GDM trophoblast cell senescence and suggests that targeting the placental ARID1A might provide new diagnostic and therapeutic strategies for GDM.

Association Between Prenatal Exposure to Organochlorine Pesticides and Telomere Length in Neonatal Cord Blood

Objectives: Environmental exposure may affect the telomere length (TL) of newborns, which is considered as an early biomarker indicating susceptibility for later life diseases. However, the effects of prenatal organochlorine pesticide (OCP) exposure on newborn TL remain unclear. This study aimed to investigate the association between prenatal exposure levels of OCPs during pregnancy and TL in neonatal cord blood. Methods: A total of 168 mother-infant pairs from a birth cohort in Wuhan, China, were included this study. The concentrations of hexachlorocyclohexanes (HCHs, including β-HCH, α-HCH, and γ-HCH), p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) and its metabolites (p,p'-dichlorodiphenyldichloroethane, p,p'-DDD; p,p'-dichlorodiphenyldichloroethylene, p,p'-DDE) were measured in cord blood. The associations between the OCPs and the TL in newborns were analyzed by a generalized linear regression model. Stratified analyses by newborn sex, maternal gestational weight gain, and pregnancy body mass index (BMI) were performed to evaluate if the associations were modified by these factors. Results: The detection rates of various OCPs ranged from 50.9% to 100.0%. The median concentration of p,p'-DDE was the highest (33.90 ng/g lipid), followed by β-HCH (8.67 ng/g lipid), and the median concentrations of the other OCPs were between 0.12 and 0.33 ng/g lipid. Among the all newborns, a two-fold increase in the γ-HCH concentration in the cord blood was significantly associated with a 0.024 (95% CI: -0.041, -0.007) decrease in the TL. After stratification by newborn sex, the inverse association between γ-HCH and the TL was only statistically significant in boys, but not in girls (P for interaction <0.05). In addition, after stratification by pre-pregnancy BMI, β-HCH and p,p'-DDT concentrations were significantly associated with a decreased TL in the overweight pre-pregnancy BMI group [-0.111 (95% CI: -0.203, -0.018) and -0.036 (95% CI: -0.049, -0.023), respectively]. Conclusions: Prenatal exposure to OCPs during pregnancy was associated with a decreased neonatal telomere length, which may be affected by the newborn sex and pre-pregnancy BMI. These findings may provide new insights into the mechanisms underlying OCP-induced adverse health effects.

Combining experiments and bioinformatics to identify transforming growth factor-β1 as a key regulator in angiotensin II-induced trophoblast senescence

INTRODUCTION

Accelerated senescence of trophoblast may cause several diverse pregnancy outcomes; however, the cause of accelerated trophoblast senescence remains unclear. The renin-angiotensin system (RAS) is closely related to organ senescence. Therefore, in the present study, we hypothesized that angiotensin (Ang)II, one of the most important RAS family members, accelerates trophoblast senescence through the transforming growth factor β-1 (TGF-β1) pathway.

METHODS

AngII and Ang1-7 were used to stimulate pregnant rats. AngII and its inhibitor olmesartan were used to stimulate trophoblast. Thereafter, senescence levels were measured. Furthermore, we used AngII to stimulate trophoblast and utilized RNA-sequencing (RNAseq) to analyze the expression of differentially expressed genes (DEGs). After identifying the overlapping genes by comparing the DEGs and senescence-related genes, we employed CytoHubba software to calculate the top five hub genes and selected TGF-β1 as the target gene. We transfected the AngII-stimulated trophoblast with TGF-β1 small interfering RNA (siRNA) and measured the senescence levels.

RESULTS

Senescence markers were upregulated in the AngII group compared with that in the control group. Furthermore, following AngII stimulation and RNAseq measurement, we identified 607 DEGs and 13 overlapping genes. The top five hub genes were as follows: PLAU, PTGS2, PDGF-β, TGF-β1, and FOXO3. Upon knockdown of TGF-β1 expression in AngII-stimulated trophoblast using TGF-β1 siRNA, we observed a downregulation of p53 and p62 mRNA expression.

DISCUSSION

AngII accelerates trophoblast senescence through the TGF-β1 pathway.

Fetal Origins of Health Disparities: Transgenerational Consequences of Racism

Despite advances in perinatal medicine, racial disparity in birth outcomes remains a public health problem in the USA. The underlying mechanisms for this long-standing racial disparity are incompletely understood. This review presents transgenerational risk factors for racial disparities in preterm birth, exploring the impact of interpersonal and structural racism, theoretical models of stress, and biological markers of racial disparities.

Influence of an exercise intervention plus an optimal Mediterranean diet adherence during pregnancy on the telomere length of the placenta. The GESTAFIT project

We aimed to investigate whether the effects of exercise on placental relative telomere length (RTL) after delivery are modulated by the Mediterranean diet [MD] adherence in 65 pregnant women (control n = 34, exercise n = 31). No differences were found in placental RTL between the exercise and the control groups (p = 0.557). The interaction-term between exercise and MD adherence with placental RTL was significant (p = 0.001). Specifically, women in the exercise group showed longer placental RTL after birth compared to controls (referent group), only for those women with a high MD adherence (mean difference = 0.467, p=0.010). A concurrent-exercise training plus an optimal MD adherence during pregnancy might prevent the placental RTL shortening.

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.

Parental Genetics Communicate with Intrauterine Environment to Reprogram Newborn Telomeres and Immunity

Telomeres, markers for cellular senescence, have been found substantially influenced by parental inheritance. It is well known that genomic stability is preserved by the DNA repair mechanism through telomerase. This study aimed to determine the association between parents−newborn telomere length (TL) and telomerase gene (TERT), highlighting DNA repair combined with TL/TERT polymorphism and immunosenescence of the triad. The mother−father−newborn triad blood samples (n = 312) were collected from Ziauddin Hospitals, Pakistan, between September 2021 and June 2022. The telomere length (T/S ratio) was quantified by qPCR, polymorphism was identified by Sanger sequencing, and immunosenescence by flow cytometry. The linear regression was applied to TL and gene association. The newborns had longest TL (2.51 ± 2.87) and strong positive association (R = 0.25, p ≤ 0.0001) (transgenerational health effects) with mothers’ TL (1.6 ± 2.00). Maternal demographics—socioeconomic status, education, and occupation—showed significant effects on TL of newborns (p < 0.015, 0.034, 0.04, respectively). The TERT risk genotype CC (rs2736100) was predominant in the triad (0.6, 0.5, 0.65, respectively) with a strong positive association with newborn TL (β = 2.91, <0.0011). Further analysis highlighted the expression of KLRG 1+ in T-cells with shorter TL but less frequent among newborns. The study concludes that TERT, parental TL, antenatal maternal health, and immunity have a significantly positive effect on the repair of newborn TL.

Oxidative stress, lipid peroxidation and premature placental senescence in preeclampsia

Accelerated placental senescence is associated with preeclampsia (PE) and other pregnancy complications. It is characterized by an accelerated decline in placental function due to the accumulation of senescence patterns such as telomere shortening, mitochondrial dysfunction, oxidative damages, increased expression of phosphorylated (serine-139) histone γ-H2AX, a sensitive marker of double-stranded DNA breaks, accumulation of cross-linked ubiquitinated proteins and sirtuin inhibition. Among the lipid oxidation products generated by the peroxidation of polyunsaturated fatty acids, aldehydes such as acrolein, 4-hydroxy-2-nonenal, 4-oxo-2-nonenal, are present in the blood and placenta from PE-affected women and could contribute to PE pathogenesis and accelerated placental aging. In this review we summarize the current knowledge on premature placental senescence and the role of oxidative stress and lipid oxidation-derived aldehydes in this process, as well as their links with PE pathogenesis. The interest of developing (or not) new therapeutic strategies targeting lipid peroxidation is discussed, the objective being a better understanding of accelerated placental aging in PE pathophysiology, and the prevention of PE bad outcomes.

Hyperglycemia First Detected in Pregnancy in South Africa: Facts, Gaps, and Opportunities

This review contextualizes hyperglycemia in pregnancy from a South-African perspective. It aims to create awareness of the importance of hyperglycemia in pregnancy in low-middle-income countries. We address unanswered questions to guide future research on sub-Saharan African women with hyperglycemia first detected in pregnancy (HFDP). South African women of childbearing age have the highest prevalence of obesity in sub-Saharan Africa. They are predisposed to Type 2 diabetes (T2DM), the leading cause of death in South African women. T2DM remains undiagnosed in many African countries, with two-thirds of people living with diabetes unaware. With the South African health policy's increased focus on improving antenatal care, women often gain access to screening for non-communicable diseases for the first time in pregnancy. While screening practices and diagnostic criteria for gestational diabetes mellitus (GDM) differ amongst geographical areas in South Africa (SA), hyperglycemia of varying degrees is often first detected in pregnancy. This is often erroneously ascribed to GDM, irrespective of the degree of hyperglycemia and not overt diabetes. T2DM and GDM convey a graded increased risk for the mother and fetus during and after pregnancy, with cardiometabolic risk accumulating across the lifespan. Resource limitations and high patient burden have hampered the opportunity to implement accessible preventative care in young women at increased risk of developing T2DM in the broader public health system in SA. All women with HFDP, including those with true GDM, should be followed and undergo glucose assessment postpartum. In SA, studies conducted early postpartum have noted persistent hyperglycemia in a third of women after GDM. Interpregnancy care is advantageous and may attain a favourable metabolic legacy in these young women, but the yield of return following delivery is suboptimal. We review the current best evidence regarding HFDP and contextualize the applicability in SA and other African or low-middle-income countries. The review identifies gaps and shares pragmatic solutions regarding clinical factors that may improve awareness, identification, diagnosis, and management of women with HFDP.

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.

Role of maternal nutrition and oxidative stress in placental telomere attrition in women with preeclampsia

Background:Maternal nutrition influences the growth and development of the fetus and influences pregnancy outcome. We have earlier demonstrated altered maternal nutrition and increased oxidative stress in women with preeclampsia. Oxidative stress is known to be associated with reduced telomere length and short telomere aggregates. Increased telomere attrition leads to increased cellular senescence and tissue ageing. Methods:The present review focuses on the role of maternal nutrition and oxidative stress in telomere attrition in preeclampsia. Results and Conclusion:Future studies need to examine the association between maternal nutritional status in early pregnancy, oxidative stress and telomere attrition in preeclampsia.

Pregnancy by Assisted Reproductive Technology Is Associated with Shorter Telomere Length in Neonates

Telomere length (TL) influences the development of lifestyle-related diseases, and neonatal TL may influence their prevalence. Various factors have been reported to affect neonatal TL. Although the fetus is exposed to multiple conditions in utero, the main factors affecting the shortening of neonatal TL are still not known. In this study, we sought to identify factors that influence fetal TL. A total of 578 mother-newborn pairs were included for TL analysis. TL was measured in genomic DNA extracted from cord blood samples using quantitative PCR. The clinical factors examined at enrollment included the following intrauterine environmental factors: maternal age, assisted reproductive technology (ART) used, body mass index (BMI), gestational diabetes mellitus (GDM), maternal stress, smoking, alcohol consumption, preterm delivery, small-for-gestational-age, neonatal sex, and placental weight. Univariate and multivariate regression analyses were used to verify the relationship between neonatal TL and these clinical factors. The median neonatal TL to single-copy gene ratio was 1.0. Pregnancy with ART was among the 11 factors associated with shorter neonatal TL. From multiple regression analysis, we determined that neonatal TL was significantly shorter for pregnancies in the ART group than in the other groups. We conclude that pregnancy with ART is associated with shorter neonatal TL.

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.

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.

Obesity is associated with shorter telomeres in 8 year-old children

Telomere length is considered a biomarker of biological aging. Shorter telomeres and obesity have both been associated with age-related diseases. To evaluate the association between various indices of obesity with leukocyte telomere length (LTL) in childhood, data from 1,396 mother-child pairs of the multi-centre European birth cohort study HELIX were used. Maternal pre-pregnancy body mass index (BMI) and 4 adiposity markers in children at age 8 (6–11) years were assessed: BMI, fat mass, waist circumference, and skinfold thickness. Relative LTL was obtained. Associations of LTL with each adiposity marker were calculated using linear mixed models with a random cohort effect. For each 1 kg/m² increment in maternal pre-pregnancy BMI, the child’s LTL was 0.23% shorter (95%CI: 0.01,0.46%). Each unit increase in child BMI z-score was associated with 1.21% (95%CI: 0.30,2.11%) shorter LTL. Inverse associations were observed between waist circumference and LTL (−0.96% per z-score unit; 95%CI: −2.06,0.16%), and skinfold thickness and LTL (−0.10% per z-score unit; 95%CI: −0.23,0.02%). In conclusion, this large multicentric study suggests that higher child adiposity indicators are associated with short telomeres in children, and that associations are stronger for child BMI than for maternal pre-pregnancy BMI.

Decreased placental apoptosis and autophagy in pregnancies complicated by gestational diabetes with large-for-gestational age fetuses

INTRODUCTION

Dysregulation of placental apoptosis and autophagy are observed in pregnancy complications including preeclampsia and fetal growth restriction. However, studies of their changes in the placentas of women with gestational diabetes mellitus (GDM) show inconsistent results. We aimed to compare the changes in apoptosis, autophagy, and Bcl-2 family proteins in the placentas from women with normal pregnancies and those with GDM, with or without large-for-gestational age (LGA) infants and to investigate the effect of hyperglycemia on the changes in apoptosis, autophagy, and Bcl-2 family proteins in primary cytotrophoblastic cells.

METHODS

Villous tissues were obtained from normal pregnant women and those with GDM, with or without LGA infants. Primary cytotrophoblast cells were isolated from normal term placentas and cultured under standard, hyperglycemic, or hyperosmotic conditions.

RESULTS

Compared to placentas from normal pregnant women, those from GDM women with LGA infants were heavier, had lower beclin-1 and DRAM levels, less M30 and cleaved PARP immunoreactivity, and increased Ki-67 immunoreactivity. These changes were associated with increased Bcl-xL and decreased Bak levels. Increased glucose concentration led to lower ATG5, beclin-1, LC3B-II, p62, and DRAM levels, lower annexin V and M30-positive cell percentages, and less cleaved PARP changes compared with standard culture conditions. Hyperglycemia caused higher Bcl-xL levels and lower Bak and Bad levels than did standard culture conditions.

DISCUSSION

There were differential changes in apoptosis and autophagy between placentas from normal pregnant women and those from GDM women with LGA infants. Bcl-2 family proteins are likely involved in the regulation of these changes.

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.

Placental Ageing in Adverse Pregnancy Outcomes: Telomere Shortening, Cell Senescence, and Mitochondrial Dysfunction

Preeclampsia is a multisystemic pregnancy disorder and a major cause of maternal and neonatal morbidity and mortality worldwide. The exact pathophysiology of preeclampsia remains unclear; however, it is speculated that the various pathologies can be attributed to impaired vascular remodelling and elevated oxidative stress within the placenta. Oxidative stress plays a key role in cell ageing, and the persistent presence of elevated oxidative stress precipitates cellular senescence and mitochondrial dysfunction, resulting in premature ageing of the placenta. Premature ageing of the placenta is associated with placental insufficiency, which reduces the functional capacity of this critical organ and leads to abnormal pregnancy outcomes. The changes brought about by oxidative insults are irreversible and often lead to deleterious modifications in macromolecules such as lipids and proteins, DNA mutations, and alteration of mitochondrial functioning and dynamics. In this review, we have summarized the current knowledge of placental ageing in the aetiology of adverse pregnancy outcomes and discussed the hallmarks of ageing which could be potential markers for preeclampsia and fetal growth restriction.

Premature placental aging in term small-for-gestational-age and growth-restricted fetuses

OBJECTIVE

To perform a comprehensive assessment of the placental aging process in small term fetuses classified as being small-for-gestational age (SGA) or having fetal growth restriction (FGR) through analysis of senescence and apoptosis markers.

METHODS

This was a prospective nested case-control study of singleton pregnancies delivered at term, including 21 control pregnancies with normally grown fetuses and 36 with a small fetus classified as SGA (birth weight between the 3^rd and 9^th percentiles and normal fetoplacental Doppler; n = 18) or FGR (birth weight < 3^rd percentile and/or abnormal cerebroplacental ratio and/or uterine artery Doppler; n = 18). Telomerase activity, telomere length (quantified by comparing the amount of amplification product for the telomere sequence (T) to that of a single copy of the gene 36B4 (S)) and RNA expression of senescence (Sirtuins 1, 3 and 6) and apoptosis (p53, p21, BAX and Caspases 3 and 9) markers (analyzed using the 2^-ΔΔCt method) were determined in placental samples collected at birth and compared between the three groups.

RESULTS

Compared to pregnancies with a normally grown fetus, both SGA and FGR pregnancies presented signs of accelerated placental aging, including lower telomerase activity (mean ± SD, 12.8 ± 6.6% in controls vs 7.98 ± 4.2% in SGA vs 7.79 ± 4.6% in FGR; P = 0.008), shorter telomeres (mean ± SD T/S ratio, 1.20 ± 0.6 in controls vs 1.08 ± 0.9 in SGA vs 0.66 ± 0.5 in FGR; P = 0.047) and reduced Sirtuin-1 RNA expression (mean ± SD 2^-ΔΔCt , 1.55 ± 0.8 in controls vs 0.91 ± 0.8 in SGA vs 0.63 ± 0.5 in FGR; P = 0.001) together with increased p53 RNA expression (median (interquartile range) 2^-ΔΔCt , 1.07 (0.3-3.3) in controls vs 5.39 (0.6-15) in SGA vs 3.75 (0.9-7.8) in FGR; P = 0.040). FGR cases presented signs of apoptosis, with increased Caspase-3 RNA levels (median (interquartile range) 2^-ΔΔCt , 0.94 (0.7-1.7) in controls vs 3.98 (0.9-31) in FGR; P = 0.031) and Caspase-9 RNA levels (median (interquartile range) 2^-ΔΔCt , 1.21 (0.6-4.0) in controls vs 3.87 (1.5-9.0) in FGR; P = 0.037) compared with controls. In addition, Sirtuin-1 RNA expression, telomerase activity, telomere length and Caspase-3 activity showed significant linear trends across groups as severity of the condition increased.

CONCLUSIONS

Accelerated placental aging was observed in both clinical forms of late-onset fetal smallness (SGA and FGR), supporting a common pathophysiology and challenging the concept of SGA fetuses being constitutionally small. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Peripheral blood telomere alterations in ground glass opacity (GGO) lesions may suggest malignancy

A ground glass opacity (GGO) lung lesion may represent early stage adenocarcinoma, which has an excellent prognosis upon prompt surgical resection. However, GGO lesions have broad differential diagnoses, including both benign and malignant lesions. Our objective was to study telomere length and telomerase activity in patients with suspected lung cancer in which GGO was the predominant radiographic feature. Knowledge of telomere biology may help distinguish malignant from benign radiographic lesions and guide risk assessment of these lesions. Peripheral blood samples were taken from 22 patients with suspected adenocarcinoma with the GGO radiographic presentation. Multidisciplinary discussion confirmed the need for surgery in all cases. We used an age and gender‐matched group without known lung disease as a control. Telomere length and aggregates were assessed by quantitative fluorescence in situ hybridization (QFISH) and quantitative PCR. Cell senescence was evaluated by senescence‐associated heterochromatin foci. Subjects with GGO lesions had a higher percentage of lymphocytes with shorter telomeres (Q‐FISH, P = 0.003). Furthermore, relative telomere length was also reduced among the GGO cases (qPCR, P < 0.05). Increased senescence was observed in the GGO group compared to controls (P < 0.001), with significant correlation between the senescence‐associated heterochromatin foci and aggregate formation (r = −0.7 and r = −0.44 for cases and controls, respectively). In conclusion, patients with resectable early adenocarcinoma demonstrate abnormal telomere length and cell senescence in peripheral blood leukocytes compared to control subjects. Abnormal telomere biology in the peripheral blood may increase suspicion of early adenocarcinoma among patients with GGO lesions.

The effect of maternal body mass index (BMI) and telomere function on in vitro fertilization (IVF) outcome: a preliminary cohort study

Telomeres are a specific base sequence of DNA, responsible for chromosome stability and DNA protection. We aimed to investigate the association between telomere systems and IVF outcomes according to patients' BMI. For all telomere characteristics, there was a distinct trend towards shorter telomeres and activation of telomere shortening compensatory mechanisms in the BMI group >25 kg/m², reaching statistical significance for senescence only (r = 0.7, p value <0.01). There was a trend towards a relationship between telomere length and number of oocytes between telomere length and fertilization rate, but these did not reach a statistical significance. For pregnancy outcome, all telomere characteristics were better for the patients who achieved a pregnancy. While there is paucity of data in the literature concerning the association between telomere characteristics and infertility, telomeres might contribute to the association between obesity and sub-optimal IVF results.

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.

Sex-specific associations between telomere length and candidate miRNA expression in placenta

BACKGROUND

In the early-life environment, proper development of the placenta is essential for both fetal and maternal health. Telomere length at birth has been related to life expectancy. MicroRNAs (miRNAs) as potential epigenetic determinants of telomere length at birth have not been identified. In this study, we investigate whether placental miRNA expression is associated with placental telomere length at birth.

METHODS

We measured the expression of seven candidate miRNAs (miR-16-5p, -20a-5p, -21-5p, -34a-5p, 146a-5p, -210-3p and -222-3p) in placental tissue at birth in 203 mother-newborn (51.7% girls) pairs from the ENVIRONAGE birth cohort. We selected miRNAs known to be involved in crucial cellular processes such as inflammation, oxidative stress, cellular senescence related to aging. Placental miRNA expression and relative average placental telomere length were measured using RT-qPCR.

RESULTS

Both before and after adjustment for potential covariates including newborn's ethnicity, gestational age, paternal age, maternal smoking status, maternal educational status, parity, date of delivery and outdoor temperature during the 3rd trimester of pregnancy, placental miR-34a, miR-146a, miR-210 and miR-222 expression were significantly (p ≤ 0.03) and positively associated with placental relative telomere length in newborn girls. In newborn boys, only higher expression of placental miR-21 was weakly (p = 0.08) associated with shorter placental telomere length. Significant miRNAs explain around 6-8% of the telomere length variance at birth.

CONCLUSIONS

Placental miR-21, miR-34a, miR-146a, miR-210 and miR-222 exhibit sex-specific associations with telomere length in placenta. Our results indicate miRNA expression in placental tissue could be an important determinant in the process of aging starting from early life onwards.

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.

Differences in placental telomere length suggest a link between racial disparities in birth outcomes and cellular aging

BACKGROUND

Health disparities begin early in life and persist across the life course. Despite current efforts, black women exhibit greater risk for pregnancy complications and negative perinatal outcomes compared with white women. The placenta, which is a complex multi-tissue organ, serves as the primary transducer of bidirectional information between the mother and fetus. Altered placental function is linked to multiple racially disparate pregnancy complications; however, little is known about racial differences in molecular factors within the placenta. Several pregnancy complications, which include preeclampsia and fetal growth restriction, exhibit racial disparities and are associated with shorter placental telomere length, which is an indicator of cellular stress and aging. Cellular senescence and telomere dynamics are linked to the molecular mechanisms that are associated with the onset of labor and parturition. Further, racial differences in telomere length are found in a range of different peripheral tissues. Together these factors suggest that exploration of racial differences in telomere length of the placenta may provide novel mechanistic insight into racial disparities in birth outcomes.

OBJECTIVE

This study examined whether telomere length measured in 4 distinct fetally derived tissues were significantly different between black and white women. The study had 2 hypotheses: (1) that telomere length that is measured in different placental tissue types would be correlated and (2) that across all sampled tissues telomere length would differ by race.

STUDY DESIGN

In a prospective study, placental tissue samples were collected from the amnion, chorion, villus, and umbilical cord from black and white singleton pregnancies (N=46). Telomere length was determined with the use of monochrome multiplex quantitative real-time polymerase chain reaction in each placental tissue. Demographic and pregnancy-related data were also collected. Descriptive statistics characterized the sample overall and among black and white women separately. The overall impact of race was assessed by multilevel mixed-effects linear regression models that included empirically relevant covariates.

RESULTS

Telomere length was correlated significantly across all placental tissues. Pairwise analyses of placental tissue telomere length revealed significantly longer telomere length in the amnion compared with the chorion (t=-2.06; P=.043). Overall telomere length measured in placenta samples from black mothers were significantly shorter than those from white mothers (β=-0.09; P=.04). Controlling for relevant maternal and infant characteristics strengthened the significance of the observed racial differences (β=-0.12; P=.02). Within tissue analyses revealed that the greatest difference by race was found in chorionic telomere length (t=-2.81; P=.007).

CONCLUSION

These findings provide the first evidence of racial differences in placental telomere length. Telomere length was significantly shorter in placental samples from black mothers compared with white mothers. Given previous studies that have reported that telomere length, cellular senescence, and telomere dynamics are molecular factors that contribute to the rupture of the amniotic sac, onset of labor, and parturition, our findings of shorter telomere length in placentas from black mothers suggest that accelerated cellular aging across placental tissues may be relevant to the increased risk of preterm delivery in black pregnancies. Our results suggest that racial differences in cellular aging in the placenta contribute to the earliest roots of health disparities.

Maternal Social Disadvantage and Newborn Telomere Length in Archived Dried Blood Spots from the Michigan Neonatal Biobank

Telomeres are the protective caps at the ends of eukaryotic chromosomes. Short telomere length is associated with morbidity and mortality among adults and may mark the biological impact of social experiences. Using archived dried blood spots from the Michigan Neonatal Biobank, this study examined markers of maternal social disadvantage (educational attainment, receipt of public assistance, marital status, and race/ethnicity) from linked birth certificates as predictors of telomere length at birth in a sample of 192 singleton neonates born to non-Hispanic black, non-Hispanic white, and Latina mothers aged 20-35 years. Consistent with two recent studies in newborns, but counter to the idea that maternal social disadvantage is associated with shorter offspring telomere length, we found that infants born to black mothers had longer telomeres than those born to white mothers (b = 0.12, SE = 0.06, p = .05). However, black/white differences in newborn telomere length varied by receipt of public assistance. Among newborns whose mothers received WIC and/or Medicaid, there were no significant black/white differences in telomere length (b = 0.09, SE = 0.08, p = .25). In contrast, among those whose mothers did not receive public assistance-just 6 out of 69 infants born to black mothers versus 41 out of 69 infants born to white mothers-we found that babies born to black mothers had longer telomere length than babies born to white mothers (b = 0.37, SE = 0.16, p = .03). The interaction between black race/ethnicity and receipt of public assistance did not reach the conventional threshold for statistical significance (b = -0.22, SE = 0.15, p = .13), suggesting that this finding may be due to chance. No other markers of maternal social disadvantage were related to infant telomere length. Although replication of these results in a larger sample with more infants born to black mothers with relatively high socioeconomic status is needed, this study offers preliminary support for the hypothesis that race/ethnic differences in newborn telomere length depend on social context.

Maternal pre-pregnancy body mass index and newborn telomere length

BACKGROUND

Newborn telomere length sets telomere length for later life. At birth, telomere length is highly variable among newborns and the environmental factors during in utero life for this observation remain largely unidentified. Obesity during pregnancy might reflect an adverse nutritional status affecting pregnancy and offspring outcomes, but the association of maternal pre-pregnancy body mass index (BMI) with newborn telomere length, as a mechanism of maternal obesity, on the next generation has not been addressed.

METHODS

Average relative telomere lengths were measured in cord blood (n = 743) and placental tissue (n = 702) samples using a quantitative real-time PCR method from newborns from the ENVIRONAGE birth cohort in Belgium. By using univariate and multivariable adjusted linear regression models we addressed the associations between pre-pregnancy BMI and cord blood and placental telomere lengths.

RESULTS

Maternal age was 29.1 years (range, 17-44) and mean (SD) pre-pregnancy BMI was 24.1 (4.1) kg/m². Decline in newborn telomere length occurred in parallel with higher maternal pre-pregnancy BMI. Independent of maternal and paternal age at birth, maternal education, gestational age, newborn gender, ethnicity, birthweight, maternal smoking status, parity, cesarean section, and pregnancy complications, each kg/m² increase in pre-pregnancy BMI was associated with a -0.50 % (95 % CI, -0.83 to -0.17 %; P = 0.003) shorter cord blood telomere length and a -0.66 % (95 % CI, -1.06 to -0.25 %; P = 0.002) shorter placental telomere length.

CONCLUSIONS

Maternal pre-pregnancy BMI is associated with shorter newborn telomere lengths as reflected by cord blood and placental telomeres. These findings support the benefits of a pre-pregnancy healthy weight for promoting molecular longevity from early life onwards.

Maternal pre-pregnancy body mass index and newborn telomere length

BACKGROUND

Newborn telomere length sets telomere length for later life. At birth, telomere length is highly variable among newborns and the environmental factors during in utero life for this observation remain largely unidentified. Obesity during pregnancy might reflect an adverse nutritional status affecting pregnancy and offspring outcomes, but the association of maternal pre-pregnancy body mass index (BMI) with newborn telomere length, as a mechanism of maternal obesity, on the next generation has not been addressed.

METHODS

Average relative telomere lengths were measured in cord blood (n = 743) and placental tissue (n = 702) samples using a quantitative real-time PCR method from newborns from the ENVIRONAGE birth cohort in Belgium. By using univariate and multivariable adjusted linear regression models we addressed the associations between pre-pregnancy BMI and cord blood and placental telomere lengths.

RESULTS

Maternal age was 29.1 years (range, 17-44) and mean (SD) pre-pregnancy BMI was 24.1 (4.1) kg/m². Decline in newborn telomere length occurred in parallel with higher maternal pre-pregnancy BMI. Independent of maternal and paternal age at birth, maternal education, gestational age, newborn gender, ethnicity, birthweight, maternal smoking status, parity, cesarean section, and pregnancy complications, each kg/m² increase in pre-pregnancy BMI was associated with a -0.50 % (95 % CI, -0.83 to -0.17 %; P = 0.003) shorter cord blood telomere length and a -0.66 % (95 % CI, -1.06 to -0.25 %; P = 0.002) shorter placental telomere length.

CONCLUSIONS

Maternal pre-pregnancy BMI is associated with shorter newborn telomere lengths as reflected by cord blood and placental telomeres. These findings support the benefits of a pre-pregnancy healthy weight for promoting molecular longevity from early life onwards.

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 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.