Articles de revues : « Sperm telomere length »

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Gentiluomo, Manuel, Alice Luddi, Annapaola Cingolani, Marco Fornili, Laura Governini, Ersilia Lucenteforte, Laura Baglietto, Paola Piomboni et Daniele Campa. « Telomere Length and Male Fertility ». International Journal of Molecular Sciences 22, n^o 8 (12 avril 2021) : 3959. http://dx.doi.org/10.3390/ijms22083959.

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Over the past decade, telomeres have attracted increasing attention due to the role they play in human fertility. However, conflicting results have been reported on the possible association between sperm telomere length (STL) and leukocyte telomere length (LTL) and the quality of the sperm parameters. The aim of this study was to run a comprehensive study to investigate the role of STL and LTL in male spermatogenesis and infertility. Moreover, the association between the sperm parameters and 11 candidate single nucleotide polymorphisms (SNPs), identified in the literature for their association with telomere length (TL), was investigated. We observed no associations between sperm parameters and STL nor LTL. For the individual SNPs, we observed five statistically significant associations with sperm parameters: considering a p < 0.05. Namely, ACYP2˗rs11125529 and decreased sperm motility (p = 0.03); PXK˗rs6772228 with a lower sperm count (p = 0.02); NAF1˗rs7675998 with increased probability of having abnormal acrosomes (p = 0.03) and abnormal flagellum (p = 0.04); ZNF208˗rs8105767 and reduction of sperms with normal heads (p = 0.009). This study suggests a moderate involvement of telomere length in male fertility; however, in our analyses four SNPs were weakly associated with sperm variables, suggesting the SNPs to be pleiotropic and involved in other regulatory mechanisms independent of telomere homeostasis, but involved in the spermatogenic process.

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Chieffi Baccari, Gabriella, Giuseppe Iurato, Alessandra Santillo et Brian Dale. « Male Germ Cell Telomeres and Chemical Pollutants ». Biomolecules 13, n^o 5 (25 avril 2023) : 745. http://dx.doi.org/10.3390/biom13050745.

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In recent decades, male infertility has been correlated with the shortening of sperm telomeres. Telomeres regulate the reproductive lifespan by mediating the synapsis and homologous recombination of chromosomes during gametogenesis. They are composed of thousands of hexanucleotide DNA repeats (TTAGGG) that are coupled to specialized shelterin complex proteins and non-coding RNAs. Telomerase activity in male germ cells ensures that the telomere length is maintained at maximum levels during spermatogenesis, despite telomere shortening due to DNA replication or other genotoxic factors such as environmental pollutants. An emerging body of evidence has associated an exposure to pollutants with male infertility. Although telomeric DNA may be one of the important targets of environmental pollutants, only a few authors have considered it as a conventional parameter for sperm function. The aim of this review is to provide comprehensive and up-to-date data on the research carried out so far on the structure/function of telomeres in spermatogenesis and the influence of environmental pollutants on their functionality. The link between pollutant-induced oxidative stress and telomere length in germ cells is discussed.

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Ribas-Maynou, Jordi, Yentel Mateo-Otero, Marina Sanchez-Quijada, Sandra Recuero, Ariadna Delgado-Bermúdez, Marc Llavanera et Marc Yeste. « Telomere Length in Pig Sperm Is Related to In Vitro Embryo Development Outcomes ». Animals 12, n^o 2 (15 janvier 2022) : 204. http://dx.doi.org/10.3390/ani12020204.

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Telomere length has attracted much interest as a topic of study in human reproduction; furthermore, the link between sperm telomere length and fertility outcomes has been investigated in other species. This biomarker, however, has not been much explored in other animals, such as pigs, and whether it is related to sperm quality and fertility outcomes remains unknown. The present work aimed to determine the absolute value of telomere length in pig sperm, as well as its relationship to sperm quality parameters and embryo development. Telomere length was determined through quantitative fluorescence in situ hybridization (qFISH) in 23 pig sperm samples and data were correlated to quality parameters (motility, morphology, and viability) and in vitro fertilization outcomes. We found that the mean telomere length in pig sperm was 22.1 ± 3.6 kb, which is longer than that previously described in humans. Whilst telomere length was not observed to be correlated to sperm quality variables (p > 0.05), a significant correlation between telomere length and the percentage of morulae 6 days after in vitro fertilization was observed (rs = 0.559; 95% C.I. = (−0.007 to 0.854); p = 0.047). Interestingly, this correlation was not found when percentages of early blastocysts/blastocysts (rs = 0.410; 95% C.I. = (−0.200 to 0.791); p = 0.164) and of hatching/hatched blastocysts (rs = 0.356; 95% C.I. = (− 0.260 to 0.766); p = 0.233) were considered. Through the separation of the samples into two groups by the median value, statistically significant differences between samples with shorter telomeres than the median and samples with longer telomeres than the median were found regarding development to morula (11.5 ± 3.6 vs. 21.8 ± 6.9, respectively) and to early blastocyst/blastocysts (7.6 ± 1.4 vs. 17.9 ± 12.2, respectively) (p < 0.05). In the light of these results, sperm telomere length may be a useful biomarker for embryo development in pigs, as sperm with longer telomeres lead to higher rates of morulae and blastocysts.

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Anifandis, George, Maria Samara, Mara Simopoulou, Christina I. Messini, Katerina Chatzimeletiou, Eleni Thodou, Alexandros Daponte et Ioannis Georgiou. « Insights into the Role of Telomeres in Human Embryological Parameters. Opinions Regarding IVF ». Journal of Developmental Biology 9, n^o 4 (13 novembre 2021) : 49. http://dx.doi.org/10.3390/jdb9040049.

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Telomeres promote genome integrity by protecting chromosome ends from the activation of the DNA damage response and protecting chromosomes from the loss of coding sequences due to the end replication problem. Telomere length (TL) is progressively shortened as age progresses, thus resulting in cellular senescence. Therefore, TL is in strong adverse linear correlation with aging. Mounting evidence supports the notion that telomeres and male/female infertility are in a close relationship, posing the biology of telomeres as a hot topic in the era of human-assisted reproduction. Specifically, the length of sperm telomeres is gradually increasing as men get older, while the telomere length of the oocytes seems not to follow similar patterns with that of sperm. Nonetheless, the telomere length of the embryos during the cleavage stages seems to have a paternal origin, but the telomere length can be further extended by telomerase activity during the blastocyst stage. The latter has been proposed as a new molecular biomarker with strong predictive value regarding male infertility. As far as the role of telomeres in assisted reproduction, the data is limited but the length of telomeres in both gametes seems to be affected mainly by the cause of infertility rather than the assisted reproductive therapy (ART) procedure itself. The present review aims to shed more light into the role of telomeres in human embryological parameters, including gametes and embryos and also presents opinions regarding the association between telomeres and in vitro fertilization (IVF).

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Eisenberg, Dan T. A., et Christopher W. Kuzawa. « The paternal age at conception effect on offspring telomere length : mechanistic, comparative and adaptive perspectives ». Philosophical Transactions of the Royal Society B : Biological Sciences 373, n^o 1741 (15 janvier 2018) : 20160442. http://dx.doi.org/10.1098/rstb.2016.0442.

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Telomeres are repeating DNA found at the ends of chromosomes that, in the absence of restorative processes, shorten with cell replications and are implicated as a cause of senescence. It appears that sperm telomere length (TL) increases with age in humans, and as a result offspring of older fathers inherit longer telomeres. We review possible mechanisms underlying this paternal age at conception (PAC) effect on TL, including sperm telomere extension due to telomerase activity, age-dependent changes in the spermatogonial stem cell population (possibly driven by ‘selfish’ spermatogonia) and non-causal confounding. In contrast to the lengthening of TL with PAC, higher maternal age at conception appears to predict shorter offspring TL in humans. We review evidence for heterogeneity across species in the PAC effect on TL, which could relate to differences in statistical power, sperm production rates or testicular telomerase activity. Finally, we review the hypothesis that the PAC effect on TL may allow a gradual multi-generational adaptive calibration of maintenance effort, and reproductive lifespan, to local demographic conditions: descendants of males who reproduced at a later age are likely to find themselves in an environment where increased maintenance effort, allowing later reproduction, represents a fitness improving resource allocation. This article is part of the theme issue ‘Understanding diversity in telomere dynamics’.

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de Frutos, C., R. Laguna-Barraza, P. Bermejo-Alvarez, D. Rizos et A. Gutierrez-Adan. « 91 SPERMATOZOA TELOMERE LENGTH DETERMINES EMBRYONIC TELOMERE LENGTH BEFORE EMBRYONIC GENOME ACTIVATION ». Reproduction, Fertility and Development 25, n^o 1 (2013) : 193. http://dx.doi.org/10.1071/rdv25n1ab91.

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A critical issue for species integrity is the existence of a telomere elongation program during embryogenesis that ensures sufficient telomere reserves in mammalian newborns. Two different mechanisms have been reported to act on telomere elongation during early embryogenesis: first, the telomerase, the ribonucleoprotein that adds telomeric repeats onto the chromosome ends, known to be responsible for the telomere lengthening at the morula-blastocyst transition in mice and bovine; second, in laboratory mice strains, mature oocytes increase the length of their relatively short telomeres between the 1-cell and 2-cell stages by a recombination or ALT-like pathway. In contrast, spermatozoa, the terminally differentiated male gametes, exhibit a very long telomere length (TL). The aim of this study was to clarify the potential role of the spermatozoa TL in the telomere lengthening occurring between oocyte and the 2-cell stage. For this purpose, we used 2 mouse species known to differ greatly in their TL [Mus musculus (hybrid C57CBAF1), long TL, and Mus spretus, short TL]. First, we compared relative TL in sperm samples from 5 age-matched males of each species by quantitative real-time PCR, with the numbers of telomere repeats being normalized, to the amount of DNA present in the sample (based on quantification of the Rn18S gene) by the comparative Ct method. Then, 1- and 2-cell embryos were produced by fertilizing Mus musculus oocytes with either Mus musculus or Mus spretus spermatozoa. The TL analysis in oocytes, zygotes, or 2-cell embryos was carried out by absolute quantification of telomere repeats by qPCR and normalized to the highest Ct observed value. Twenty to thirty samples per stage were analyzed, with each sample consisting in 2 matured oocytes, 2 zygotes, or one 2-cell embryo, to allow comparisons between stages. One-way ANOVA was used for statistical analysis. Mus spretus spermatozoa had significantly shorter telomeres than did Mus musculus (1.0 ± 0.1 v. 9.0 ± 1.5, respectively; P ≤ 0.01). The TL increased after fertilization from oocyte to zygote and 2-cell embryo stages in Mus musculus (1.0 ± 0.1, 1.5 ± 0.1, and 2.4 ± 0.2, respectively; P ≤ 0.01). In contrast, no differences were found in the TLs between the 3 stages in Mus spretus hybrids (oocyte: 1.0 ± 0.1; zygote: 1.0 ± 0.1; and 2-cell embryo: 1.0 ± 0.1), indicating that no elongation occurred after fertilization with spermatozoa with short telomeres. Herein, we demonstrated that before embryonic genome activation occurs, spermatozoa TL determines TL of the early embryo, suggesting that spermatozoon telomeres may act as recombination templates for early telomere lengthening right after syngamia.

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Pauliny, Angela, Emily Miller, Nicky Rollings, Erik Wapstra, Donald Blomqvist, Chris R. Friesen et Mats Olsson. « Effects of male telomeres on probability of paternity in sand lizards ». Biology Letters 14, n^o 8 (août 2018) : 20180033. http://dx.doi.org/10.1098/rsbl.2018.0033.

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Standardized swim-up trials are used in in vitro fertilization clinics to select particularly motile spermatozoa in order to increase the probability of a successful fertilization. Such trials demonstrate that sperm with longer telomeres have higher motility and lower levels of DNA damage. Regardless of whether sperm motility, and successful swim-up to fertilization sites, is a direct or correlational effect of telomere length or DNA damage, covariation between telomere length and sperm performance predicts a relationship between telomere length and probability of paternity in sperm competition, a prediction that for ethical reasons cannot be tested on humans. Here, we test this prediction in sand lizards ( Lacerta agilis ) using experimental data from twice-mated females in a laboratory population, and telomere length in blood from the participating lizards. Female identity influenced paternity (while the mechanism was not identified), while relatively longer male telomeres predicted higher probability of paternity. We discuss potential mechanisms underpinning this result.

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Fice, Heather, et Bernard Robaire. « Telomere Dynamics Throughout Spermatogenesis ». Genes 10, n^o 7 (12 juillet 2019) : 525. http://dx.doi.org/10.3390/genes10070525.

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Telomeres are repeat regions of DNA that cap either end of each chromosome, thereby providing stability and protection from the degradation of gene-rich regions. Each cell replication causes the loss of telomeric repeats due to incomplete DNA replication, though it is well-established that progressive telomere shortening is evaded in male germ cells by the maintenance of active telomerase. However, germ cell telomeres are still susceptible to disruption or insult by oxidative stress, toxicant exposure, and aging. Our aim was to examine the relative telomere length (rTL) in an outbred Sprague Dawley (SD) and an inbred Brown Norway (BN) rat model for paternal aging. No significant differences were found when comparing pachytene spermatocytes (PS), round spermatids (RS), and sperm obtained from the caput and cauda of the epididymis of young and aged SD rats; this is likely due to the high variance observed among individuals. A significant age-dependent decrease in rTL was observed from 115.6 (±6.5) to 93.3 (±6.3) in caput sperm and from 142.4 (±14.6) to 105.3 (±2.5) in cauda sperm from BN rats. Additionally, an increase in rTL during epididymal maturation was observed in both strains, most strikingly from 115.6 (±6.5) to 142 (±14.6) in young BN rats. These results confirm the decrease in rTL in rodents, but only when an inbred strain is used, and represent the first demonstration that rTL changes as sperm transit through the epididymis.

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Fattet, Anne-Julie, Maxime Chaillot et Isabelle Koscinski. « Telomere Length, a New Biomarker of Male (In)Fertility ? A Systematic Review of the Literature ». Genes 14, n^o 2 (7 février 2023) : 425. http://dx.doi.org/10.3390/genes14020425.

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Male factors are suspected in around half cases of infertility, of which up to 40% are diagnosed as idiopathic. In the context of a continuously increased resort to ART and increased decline of semen parameters, it is of greatest interest to evaluate an additional potential biomarker of sperm quality. According to PRISMA guidelines, this systematic review of the literature selected studies evaluating telomere length in sperm and/or in leukocytes as a potential male fertility biomarker. Twenty-two publications (3168 participants) were included in this review of experimental evidence. For each study, authors determined if there was a correlation between telomere length and semen parameters or fertility outcomes. Of the 13 studies concerning sperm telomere length (STL) and semen parameters, ten found an association between short STL and altered parameters. Concerning the impact of STL on ART results, the data are conflicting. However, eight of the 13 included studies about fertility found significantly longer sperm telomeres in fertile men than in infertile men. In leukocytes, the seven studies reported conflicting findings. Shorter sperm telomeres appear to be associated with altered semen parameters or male infertility. Telomere length may be considered as a new molecular marker of spermatogenesis and sperm quality, and thus is related to male fertility potential. However, additional studies are needed to define the place of the STL in the assessment of individual fertility.

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Aviv, Abraham. « The mitochondrial genome, paternal age and telomere length in humans ». Philosophical Transactions of the Royal Society B : Biological Sciences 373, n^o 1741 (15 janvier 2018) : 20170210. http://dx.doi.org/10.1098/rstb.2017.0210.

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Telomere length (TL) in humans is highly heritable and undergoes progressive age-dependent shortening in somatic cells. By contrast, sperm donated by older men display comparatively long telomeres, presumably because in the male germline, telomeres become longer with age. This puzzling phenomenon might explain why TL in the offspring correlates positively with paternal age. The present communication proposes that mitochondrial DNA polymorphisms and heteroplasmy cause variation in the production of reactive oxygen species, which, in turn, mediate age-dependent selection of germ stem cells with long telomeres and hence sperm with long telomeres. These long telomeres are then inherited by the offspring. The effect of paternal age on the offspring TL might be an evolutionarily driven mechanism that helps regulate TL across the human population. This article is part of the theme issue ‘Understanding diversity in telomere dynamics’.

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Sharqawi, Moamina, Shay Hantisteanu, Asaf Bilgory, Nardin Aslih, Yasmin Shibli Abu Raya, Yuval Atzmon, Daniela Estrada, Ofer Limonad, Shilhav Meisel-Sharon et Einat Shalom-Paz. « The Impact of Lifestyle on Sperm Function, Telomere Length, and IVF Outcomes ». American Journal of Men's Health 16, n^o 5 (septembre 2022) : 155798832211199. http://dx.doi.org/10.1177/15579883221119931.

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Many risk factors can potentially influence sperm quality. Telomeres confer stability on the chromosome and their dysfunction has been implicated in conditions such as cancer, aging, and lifestyle. The impact of lifestyle on sperm cell telomeres is unclear. The objectives of this study were to evaluate the impact of lifestyle behaviors on telomere length in sperm and to follow the correlation with pregnancy outcomes in patients undergoing in vitro fertilization (IVF). In this prospective observational study, sperm was analyzed for telomere length (TL). Men were asked to report lifestyle behaviors including occupation (physical or sedentary), smoking duration and amount, physical activity, dietary habits, and where they keep their cellular phone (bag, pants, or shirt pocket). Correlations among semen analysis, TL, men’s habits, and embryo quality and pregnancy outcomes were evaluated. Among 34 patients recruited, 12 had longer TL and 13 shorter TL. Sperm motility was negatively correlated with TL (Pearson correlation = −.588, p = .002). Smoking adversely affected native sperm motility (53% motility in nonsmokers vs. 37% in smokers; p = .006). However, there was no significant impact on TL. The group with longer telomeres demonstrated significant association with healthy diet (10/12 vs. 6/13; p = .05) and a trend toward more sports activity, weekly (16/84 vs. 7/91; p = .04) compared with the shorter telomeres group. This study suggests that lifestyle, healthy diet, and sports activity are associated with long telomeres in sperm. Sperm quality is also influenced by patients’ habits. The study strongly recommends maintaining a healthy lifestyle to preserve general health and fertility.

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Moustakli, Efthalia, Athanasios Zikopoulos, Charikleia Skentou, Stefanos Dafopoulos, Sofoklis Stavros, Konstantinos Dafopoulos, Peter Drakakis, Ioannis Georgiou et Athanasios Zachariou. « Association of Obesity with Telomere Length in Human Sperm ». Journal of Clinical Medicine 13, n^o 7 (8 avril 2024) : 2150. http://dx.doi.org/10.3390/jcm13072150.

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Background: Telomere attrition and mitochondrial dysfunction are two fundamental aspects of aging. Calorie restriction (CR) is the best strategy to postpone aging since it can enhance telomere attrition, boost antioxidant capacity, and lower the generation of reactive oxygen species (ROS). Since ROS is produced by mitochondria and can readily travel to cell nuclei, it is thought to be a crucial molecule for information transfer between mitochondria and cell nuclei. Important variables that affect the quality and functionality of sperm and may affect male reproductive health and fertility include telomere length, mitochondrial content, and the ratio of mitochondrial DNA (mtDNA) to nuclear DNA (nDNA). Telomere damage results from mitochondrial failure, whereas nuclear DNA remains unaffected. This research aims to investigate potential associations between these three variables and how they might relate to body mass index. Methods: Data were collected from 82 men who underwent IVF/ICSI at the University Hospital of Ioannina’s IVF Unit in the Obstetrics and Gynecology Department. Evaluations included sperm morphology, sperm count, sperm motility, and participant history. To address this, male participants who were categorized into three body mass index (ΒΜΙ) groups—normal, overweight, and obese—had their sperm samples tested. Results: For both the normal and overweight groups, our results show a negative connection between relative telomere length and ΒΜI. As an illustration of a potential connection between mitochondrial health and telomere maintenance, a positive correlation was found for the obese group. Only the obese group’s results were statistically significant (p < 0.05). More evidence that longer telomeres are associated with lower mitochondrial content can be found in the negative connection between telomere length and mitochondrial content in both the normal and overweight groups. However, the obese group showed a positive association. The data did not reach statistical significance for any of the three groups. These associations may affect sperm quality since telomere length and mitochondrial concentration are indicators of cellular integrity and health. Moreover, the ratio of mtDNA to nDNA was positively correlated with the relative telomere lengths of the obese group, but negatively correlated with the normal and overweight groups. In every group that was studied, the results were not statistically significant. According to this, male fertility may be negatively impacted by an imbalance in the copy number of the mitochondrial genome compared to the nuclear DNA in sperm. Conclusions: Essentially, the goal of our work is to determine whether mitochondria and telomere length in human sperm interact. Understanding these connections may aid in the explanation of some male infertility causes and possibly contribute to the creation of new treatment modalities for problems pertaining to reproductive health. The functional implications of these connections and their applications in therapeutic settings require further investigation.

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Graniel, Jacqueline V., Kamlesh Bisht, Ann Friedman, James White, Eric Perkey, Ashley Vanderbeck, Alina Moroz et al. « Differential impact of a dyskeratosis congenita mutation in TPP1 on mouse hematopoiesis and germline ». Life Science Alliance 5, n^o 1 (13 octobre 2021) : e202101208. http://dx.doi.org/10.26508/lsa.202101208.

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Telomerase extends chromosome ends in somatic and germline stem cells to ensure continued proliferation. Mutations in genes critical for telomerase function result in telomeropathies such as dyskeratosis congenita, frequently resulting in spontaneous bone marrow failure. A dyskeratosis congenita mutation in TPP1 (K170∆) that specifically compromises telomerase recruitment to telomeres is a valuable tool to evaluate telomerase-dependent telomere length maintenance in mice. We used CRISPR-Cas9 to generate a mouse knocked in for the equivalent of the TPP1 K170∆ mutation (TPP1 K82∆) and investigated both its hematopoietic and germline compartments in unprecedented detail. TPP1 K82∆ caused progressive telomere erosion with increasing generation number but did not induce steady-state hematopoietic defects. Strikingly, K82∆ caused mouse infertility, consistent with gross morphological defects in the testis and sperm, the appearance of dysfunctional seminiferous tubules, and a decrease in germ cells. Intriguingly, both TPP1 K82∆ mice and previously characterized telomerase knockout mice show no spontaneous bone marrow failure but rather succumb to infertility at steady-state. We speculate that telomere length maintenance contributes differently to the evolutionary fitness of humans and mice.

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Rocca, Maria Santa, Ludovica Dusi, Andrea Di Nisio, Erminia Alviggi, Benedetta Iussig, Sara Bertelle, Luca De Toni, Andrea Garolla, Carlo Foresta et Alberto Ferlin. « TERRA : A Novel Biomarker of Embryo Quality and Art Outcome ». Genes 12, n^o 4 (25 mars 2021) : 475. http://dx.doi.org/10.3390/genes12040475.

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Telomeres are considered to be an internal biological clock, and their progressive shortening has been associated with the risk of age-related diseases and reproductive alterations. Over recent years, an increasing number of studies have focused on the association between telomere length and fertility, identifying sperm telomere length (STL) as a novel biomarker of male fertility. Although typically considered to be repeated DNA sequences, telomeres have recently been shown to also include a long non-coding RNA (lncRNA) known as TERRA (telomeric repeat-containing RNAs). Interestingly, males with idiopathic infertility show reduced testicular TERRA expression, suggesting a link between TERRA and male fertility. The aim of this study was to investigate the role of seminal TERRA expression in embryo quality. To this end, STL and TERRA expression were quantified by Real Time qPCR in the semen of 35 men who underwent assisted reproductive technologies (ART) and 30 fertile men. We found that TERRA expression in semen and STL was reduced in patients that underwent ART (both p < 0.001). Interestingly, TERRA and STL expressions were positively correlated (p = 0.010), and TERRA expression was positively associated with embryo quality (p < 0.001). These preliminary findings suggest a role for TERRA in the maintenance of sperm telomere integrity during gametogenesis, and for the first time, TERRA expression was found as a predictive factor for embryo quality in the setting of assisted reproduction.

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Dhillon, Varinderpal S., Mohammad Shahid, Permal Deo et Michael Fenech. « Reduced SIRT1 and SIRT3 and Lower Antioxidant Capacity of Seminal Plasma Is Associated with Shorter Sperm Telomere Length in Oligospermic Men ». International Journal of Molecular Sciences 25, n^o 2 (5 janvier 2024) : 718. http://dx.doi.org/10.3390/ijms25020718.

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Infertility affects millions of couples worldwide and has a profound impact not only on their families, but also on communities. Telomere attrition has been associated with infertility, DNA damage and fragmentation. Oxidative stress has been shown to affect sperm DNA integrity and telomere length. Sirtuins such as SIRT1 and SIRT3 are involved in aging and oxidative stress response. The aim of the present study is to determine the role of SIRT1 and SIRT3 in regulating oxidative stress, telomere shortening, and their association with oligospermia. Therefore, we assessed the protein levels of SIRT1 and SIRT3, total antioxidant capacity (TAC), superoxide dismutase (SOD), malondialdehyde (MDA) and catalase activity (CAT) in the seminal plasma of 272 patients with oligospermia and 251 fertile men. We also measured sperm telomere length (STL) and leukocyte telomere length (LTL) using a standard real-time quantitative PCR assay. Sperm chromatin and protamine deficiency were also measured as per standard methods. Our results for oligospermic patients demonstrate significant reductions in semen parameters, shorter STL and LTL, lower levels of SOD, TAC, CAT, SIRT1 and SIRT3 levels, and also significant protamine deficiency and higher levels of MDA and DNA fragmentation. We conclude that a shorter TL in sperms and leukocytes is associated with increased oxidative stress that also accounts for high levels of DNA fragmentation in sperms. Our results support the hypothesis that various sperm parameters in the state of oligospermia are associated with or caused by reduced levels of SIRT1 and SIRT3 proteins.

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Turner, Kara J., Eleanor M. Watson, Benjamin M. Skinner et Darren K. Griffin. « Telomere Distribution in Human Sperm Heads and Its Relation to Sperm Nuclear Morphology : A New Marker for Male Factor Infertility ? » International Journal of Molecular Sciences 22, n^o 14 (15 juillet 2021) : 7599. http://dx.doi.org/10.3390/ijms22147599.

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Infertility is a problem affecting an increasing number of couples worldwide. Currently, marker tests for male factor infertility are complex, highly technical and relatively subjective. Up to 40% of cases of male factor infertility are currently diagnosed as idiopathic therefore, there is a clear need for further research into better ways of diagnosing it. Changes in sperm telomere length have been associated with infertility and closely linked to DNA damage and fragmentation, which are also known to be related to infertility. However, telomere distribution is a parameter thus far underexplored as an infertility marker. Here, we assessed morphological parameters of sperm nuclei in fertile control and male factor infertile cohorts. In addition, we used 2D and 3D fluorescence in situ hybridization (FISH) to compare telomere distribution between these two groups. Our findings indicate that the infertile cohort sperm nuclei were, on average, 2.9% larger in area and showed subtle differences in sperm head height and width. Telomeres were mainly distributed towards the periphery of the nuclei in the control cohort, with diminishing telomere signals towards the center of the nuclei. Sperm nuclei of infertile males, however, had more telomere signals towards the center of the nuclei, a finding supported by 3D imaging. We conclude that, with further development, both morphology and telomere distribution may prove useful investigative tools in the fertility clinic.

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de Lange, T., L. Shiue, R. M. Myers, D. R. Cox, S. L. Naylor, A. M. Killery et H. E. Varmus. « Structure and variability of human chromosome ends ». Molecular and Cellular Biology 10, n^o 2 (février 1990) : 518–27. http://dx.doi.org/10.1128/mcb.10.2.518-527.1990.

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Mammalian telomeres are thought to be composed of a tandem array of TTAGGG repeats. To further define the type and arrangement of sequences at the ends of human chromosomes, we developed a direct cloning strategy for telomere-associated DNA. The method involves a telomere enrichment procedure based on the relative lack of restriction endonuclease cutting sites near the ends of human chromosomes. Nineteen (TTAGGG)n-bearing plasmids were isolated, two of which contain additional human sequences proximal to the telomeric repeats. These telomere-flanking sequences detect BAL 31-sensitive loci and thus are located close to chromosome ends. One of the flanking regions is part of a subtelomeric repeat that is present at 10 to 25% of the chromosome ends in the human genome. This sequence is not conserved in rodent DNA and therefore should be a helpful tool for physical characterization of human chromosomes in human-rodent hybrid cell lines; some of the chromosomes that may be analyzed in this manner have been identified, i.e., 7, 16, 17, and 21. The minimal size of the subtelomeric repeat is 4 kilobases (kb); it shows a high frequency of restriction fragment length polymorphisms and undergoes extensive de novo methylation in somatic cells. Distal to the subtelomeric repeat, the chromosomes terminate in a long region (up to 14 kb) that may be entirely composed of TTAGGG repeats. This terminal segment is unusually variable. Although sperm telomeres are 10 to 14 kb long, telomeres in somatic cells are several kilobase pairs shorter and very heterogeneous in length. Additional telomere reduction occurs in primary tumors, indicating that somatic telomeres are unstable and may continuously lose sequences from their termini.

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de Lange, T., L. Shiue, R. M. Myers, D. R. Cox, S. L. Naylor, A. M. Killery et H. E. Varmus. « Structure and variability of human chromosome ends. » Molecular and Cellular Biology 10, n^o 2 (février 1990) : 518–27. http://dx.doi.org/10.1128/mcb.10.2.518.

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Mammalian telomeres are thought to be composed of a tandem array of TTAGGG repeats. To further define the type and arrangement of sequences at the ends of human chromosomes, we developed a direct cloning strategy for telomere-associated DNA. The method involves a telomere enrichment procedure based on the relative lack of restriction endonuclease cutting sites near the ends of human chromosomes. Nineteen (TTAGGG)n-bearing plasmids were isolated, two of which contain additional human sequences proximal to the telomeric repeats. These telomere-flanking sequences detect BAL 31-sensitive loci and thus are located close to chromosome ends. One of the flanking regions is part of a subtelomeric repeat that is present at 10 to 25% of the chromosome ends in the human genome. This sequence is not conserved in rodent DNA and therefore should be a helpful tool for physical characterization of human chromosomes in human-rodent hybrid cell lines; some of the chromosomes that may be analyzed in this manner have been identified, i.e., 7, 16, 17, and 21. The minimal size of the subtelomeric repeat is 4 kilobases (kb); it shows a high frequency of restriction fragment length polymorphisms and undergoes extensive de novo methylation in somatic cells. Distal to the subtelomeric repeat, the chromosomes terminate in a long region (up to 14 kb) that may be entirely composed of TTAGGG repeats. This terminal segment is unusually variable. Although sperm telomeres are 10 to 14 kb long, telomeres in somatic cells are several kilobase pairs shorter and very heterogeneous in length. Additional telomere reduction occurs in primary tumors, indicating that somatic telomeres are unstable and may continuously lose sequences from their termini.

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Antunes, D. M. F., K. H. Kalmbach, F. Wang, M. L. Seth-Smith, F. B. Kohlrausch et D. L. Keefe. « Sperm telomere length varies extensively within specimens ». Fertility and Sterility 100, n^o 3 (septembre 2013) : S224. http://dx.doi.org/10.1016/j.fertnstert.2013.07.1281.

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Kimura, Masayuki, Lynn F. Cherkas, Bernet S. Kato, Serkalem Demissie, Jacob B. Hjelmborg, Michael Brimacombe, Adrienne Cupples et al. « Offspring's Leukocyte Telomere Length, Paternal Age, and Telomere Elongation in Sperm ». PLoS Genetics 4, n^o 2 (15 février 2008) : e37. http://dx.doi.org/10.1371/journal.pgen.0040037.

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Kimura, Masayuki, Lynn Cherkas, Bernet Kato, Serkalem Demissie, Jacob Hjelmborg, Michael Brimcombe, Adrienne Cupples et al. « Offspring's Leukocyte Telomere Length, Paternal Age, and Telomere Elongation in Sperm ». PLoS Genetics preprint, n^o 2008 (2005) : e37. http://dx.doi.org/10.1371/journal.pgen.0040037.eor.

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Ankur, Mona Sharma, Ashutosh Halder, Rima Dada, Reeta Mahey et Neeraj Kumar. « Effect of Oxidative Stress on Sperm TERRA Expression and Chromatin Function in Infertile Males : A Preliminary Finding ». Journal of Scientific Research and Reports 30, n^o 10 (19 octobre 2024) : 947–59. http://dx.doi.org/10.9734/jsrr/2024/v30i102516.

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Telomeres are vital for cellular function. Oxidative stress is detrimental to telomere function as it causes telomere attrition. Increase in oxidative stress has a negative impact on sperm telomere and chromatin integrity and therefore, on sperm function and male fertility. TERRA, a long non-coding RNA is a fundamental component required for telomere length homeostasis. Aim: The present work aimed to study the effect of H2O2 induced oxidative stress on sperm TERRA expression and chromatin function. Methodology: 5 infertile and 5 fertile males were selected for the study. Baseline semen analysis was done as per WHO manual 2021. Sperm TERRA expression was assessed by real time qPCR. To assess chromatin function nuclear chromatin decondensation test was done. Results: Study showed that 500µM H2O2 increased TERRA expression as compared to untreated groups and the difference was found to be statistically significant. As compared to controls, cases showed more fold increase in TERRA expression. When treated samples of control and cases were compared, cases had more TERRA expression than controls however, the baseline TERRA expressions in untreated samples were less in cases as compared to controls. Both comparisons yielded statistically nonsignificant results. When nuclear chromatin decondensation was compared before and after H2O2 treatment, the percentage of sperm head decondensation decreased in both cases and controls. When treated and untreated samples of cases and controls were compared, the difference was statistically nonsignificant. Conclusion: Oxidative stress led to an increase in the expression of sperm TERRA and had a negative impact on nuclear chromatin decondensation. Similar studies with greater sample size can provide much more insight into TERRA mediated regulation of telomere function and chromatin integrity and how it is affected by oxidative stress.

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Berby, Benoit, Cynthia Bichara, Aurélie Rives-Feraille, Fanny Jumeau, Pierre Di Pizio, Véronique Sétif, Louis Sibert, Ludovic Dumont, Chistine Rondanino et Nathalie Rives. « Oxidative Stress Is Associated with Telomere Interaction Impairment and Chromatin Condensation Defects in Spermatozoa of Infertile Males ». Antioxidants 10, n^o 4 (12 avril 2021) : 593. http://dx.doi.org/10.3390/antiox10040593.

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Telomere length can be influenced by reactive oxygen species (ROS) generated by lifestyle factors or environmental exposure. We sought to determine whether oxidative stress has an impact on sperm nuclear alterations, especially on chromatin organization and telomere interactions in the spermatozoa of infertile males. We performed an observational and prospective study including fifty-two males, allocated in the “case group” (30 infertile males presenting conventional semen parameter alterations) and the “control group” (22 males with normal conventional semen parameters). ROS detection was determined on spermatozoa using CellROX© probes. Sperm nuclear damage was assessed using quantitative fluorescence in situ hybridization (Q-FISH) for relative telomere length and telomere number, aniline blue staining for chromatin condensation, terminal deoxynucleotidyl transferase dUTP nick-end labeling for DNA fragmentation, and FISH for aneuploidy and 8-hydroxy-2′-deoxyguanosine immunostaining for oxidative DNA damages. Infertile males had significantly increased levels of cytoplasmic ROS and chromatin condensation defects as well as a higher mean number of telomere signals per spermatozoon in comparison with controls. In addition, the mean number of sperm telomere signals were positively correlated with the percentage of spermatozoa with chromatin condensation defect. In infertile males with conventional semen parameter alterations, oxidative stress is associated with telomere interaction impairment and chromatin condensation defects.

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Lafuente, R., E. Bosch-Rue, J. Ribas-Maynou, J. Alvarez, C. Brassesco, M. J. Amengual, J. Benet, A. Garcia-Peiró et M. Brassesco. « Sperm telomere length in motile sperm selection techniques : A qFISH approach ». Andrologia 50, n^o 2 (11 juillet 2017) : e12840. http://dx.doi.org/10.1111/and.12840.

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MEDHAT HASHEM, Ph.D. and OMAIMA., ABDELRAHMAN A. ABDELRAHMAN, Ph D. ;. « Impact of Sperm Telomere Length on Sperm Quality and Male Fertility ». Medical Journal of Cairo University 92, n^o 12 (1 décembre 2024) : 1059–66. https://doi.org/10.21608/mjcu.2024.411332.

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Gouhier, Charlène, Hanae Pons-Rejraji, Sandra Dollet, Laure Chaput, Céline Bourgne, Marc Berger, Bruno Pereira, Andrei Tchirkov et Florence Brugnon. « Freezing Does Not Alter Sperm Telomere Length despite Increasing DNA Oxidation and Fragmentation ». Genes 14, n^o 5 (3 mai 2023) : 1039. http://dx.doi.org/10.3390/genes14051039.

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Correlations were reported between sperm telomere length (STL) and male fertility, sperm DNA fragmentation, and oxidation. Sperm freezing is widely used for assisted reproductive techniques, fertility preservation, and sperm donation. However, its impact on STL remains unknown. For this study, semen surplus from patients who underwent routine semen analysis were used. The impact of slow freezing on STL was analyzed by performing qPCR before and after freezing. Sperm populations with different STL were evaluated using Q-FISH. The relationship between sperm DNA oxidation, DNA fragmentation, and STL was assessed in fresh and frozen sperm samples. No significant impact of slow freezing on STL was observed, neither measured by qPCR nor Q-FISH. However, Q-FISH allowed for the distinguishing of sperm populations with different STLs within individual sperm samples. Slow freezing induced different STL distributions for some of the analyzed sperm samples, but no correlation was found between STL and sperm DNA fragmentation or oxidation. Slow freezing does not alter STL despite increasing sperm DNA oxidation and fragmentation. As STL alterations could be transmitted to offspring, the lack of impact of the slow freezing method on STL ensures the safety of this procedure.

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Rajesh, Kate Deepali, Puranam Vatsalaswamy et Manvikar Purshotam Rao. « The association of male infertility with telomere length : A case control study ». Indian Journal of Clinical Anatomy and Physiology 8, n^o 4 (15 mars 2022) : 325–32. http://dx.doi.org/10.18231/j.ijcap.2021.070.

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To study the relevance of sperm telomere length and infertility in men.: Our case-control study included twenty-five males in couple, who were subfertile/infertil (test group) and twenty-five healthy males (control group) with proven paternity in the age group 21-35 years. The Absolute Sperm Telomere length (aSTL) was measured by real-time PCR. We investigated whether any significant difference in the aSTL value existed between the groups and analysed the relationship between aSTL and other sperm parameters.The mean (SE) aSTL recorded in the infertile cases was significantly shorter than for the control group; 140.60 (6.66) Kb/genome and 239.63 (12.32) Kb/genome respectively (p <0.001) A moderate positive correlation was eminent between aSTL kb/genome and the total sperm count mil/ml (rho= 0.54, p<0.001), progressive sperm motility (rho= 0.56, p=<0.001) and sperm viability (rho= 0.51 p=0.032) in the infertile group. The measurement of aSTL by real-time PCR is a simple and rapid method that offers further paramount information with respective to the quality of sperm. It is befitted for epidemiological studies, hence opening new perspectives in the evaluation of male infertility. Our study was confined to men aged between 21-35 years. Further comparative studies are needed to explore the significance of STL and infertility in older males. Additional studies will help illumine the significance of aSTL as a prognostic biomarker in assisted reproduction.

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Rocca, M. S., E. Speltra, M. Menegazzo, A. Garolla, C. Foresta et A. Ferlin. « Sperm telomere length as a parameter of sperm quality in normozoospermic men ». Human Reproduction 31, n^o 6 (6 avril 2016) : 1158–63. http://dx.doi.org/10.1093/humrep/dew061.

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Niederberger, Craig. « Re : Sperm Telomere Length as a Parameter of Sperm Quality in Normozoospermic Men ». Journal of Urology 197, n^o 4 (avril 2017) : 1135–36. http://dx.doi.org/10.1016/j.juro.2016.12.118.

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Mishra, Swetasmita, Rajeev Kumar, Neena Malhotra, Neeta Singh et Rima Dada. « Mild oxidative stress is beneficial for sperm telomere length maintenance ». World Journal of Methodology 6, n^o 2 (2016) : 163. http://dx.doi.org/10.5662/wjm.v6.i2.163.

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Thilagavathi, J., M. Kumar, S. S. Mishra, S. Venkatesh, R. Kumar et R. Dada. « Analysis of sperm telomere length in men with idiopathic infertility ». Archives of Gynecology and Obstetrics 287, n^o 4 (20 novembre 2012) : 803–7. http://dx.doi.org/10.1007/s00404-012-2632-8.

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Carreira, Janaina Torres, Hiba Abi Hussein, Sadiya Sadiq Shiek, Loic Lesobre et Yves Hingrat. « Drivers of sperm telomere length variability in a wild bird ». Animal Reproduction Science 272 (janvier 2025) : 107746. https://doi.org/10.1016/j.anireprosci.2024.107746.

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Ferlin, A., E. Rampazzo, M. S. Rocca, S. Keppel, A. C. Frigo, A. De Rossi et C. Foresta. « In young men sperm telomere length is related to sperm number and parental age ». Human Reproduction 28, n^o 12 (27 octobre 2013) : 3370–76. http://dx.doi.org/10.1093/humrep/det392.

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Iannuzzi, Alessandra, Giovanni Della Valle, Marco Russo, Valentina Longobardi, Giuseppe Albero, Carolina De Canditiis, Michal Andrzej Kosior, Ramona Pistucci et Bianca Gasparrini. « Evaluation of bovine sperm telomere length and association with semen quality ». Theriogenology 158 (décembre 2020) : 227–32. http://dx.doi.org/10.1016/j.theriogenology.2020.09.019.

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Niederberger, Craig. « Re : Analysis of Sperm Telomere Length in Men with Idiopathic Infertility ». Journal of Urology 189, n^o 5 (mai 2013) : 1842. http://dx.doi.org/10.1016/j.juro.2013.02.060.

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Lu, Zhong-Hua, Bin Sun, Yi-Xin Wang, Ya-Ru Wu, Yu-Jie Chen, Sheng-Zhi Sun, Shi-Jia Liang et al. « Ozone exposure associates with sperm quality indicators : Sperm telomere length as a potential mediating factor ». Journal of Hazardous Materials 459 (octobre 2023) : 132292. http://dx.doi.org/10.1016/j.jhazmat.2023.132292.

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Pendina, Anna A., Mikhail I. Krapivin, Olga A. Efimova, Andrei V. Tikhonov, Irina D. Mekina, Evgeniia M. Komarova, Alla S. Koltsova et al. « Telomere Length in Metaphase Chromosomes of Human Triploid Zygotes ». International Journal of Molecular Sciences 22, n^o 11 (25 mai 2021) : 5579. http://dx.doi.org/10.3390/ijms22115579.

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The human lifespan is strongly influenced by telomere length (TL) which is defined in a zygote—when two highly specialised haploid cells form a new diploid organism. Although TL is a variable parameter, it fluctuates in a limited range. We aimed to establish the determining factors of TL in chromosomes of maternal and paternal origin in human triploid zygotes. Using Q-FISH, we examined TL in the metaphase chromosomes of 28 human triploid zygotes obtained from 22 couples. The chromosomes’ parental origin was identified immunocytochemically through weak DNA methylation and strong hydroxymethylation in the sperm-derived (paternal) chromosomes versus strong DNA methylation and weak hydroxymethylation in the oocyte-derived (maternal) ones. In 24 zygotes, one maternal and two paternal chromosome sets were identified, while the four remaining zygotes contained one paternal and two maternal sets. For each zygote, we compared mean relative TLs between parental chromosomes, identifying a significant difference in favour of the paternal chromosomes, which attests to a certain “imprinting” of these regions. Mean relative TLs in paternal or maternal chromosomes did not correlate with the respective parent’s age. Similarly, no correlation was observed between the mean relative TL and sperm quality parameters: concentration, progressive motility and normal morphology. Based on the comparison of TLs in chromosomes inherited from a single individual’s gametes with those in chromosomes inherited from different individuals’ gametes, we compared intraindividual (intercellular) and interindividual variability, obtaining significance in favour of the latter and thus validating the role of heredity in determining TL in zygotes. A comparison of the interchromatid TL differences across the chromosomes from sets of different parental origin with those from PHA-stimulated lymphocytes showed an absence of a significant difference between the maternal and paternal sets but a significant excess over the lymphocytes. Therefore, interchromatid TL differences are more pronounced in zygotes than in lymphocytes. To summarise, TL in human zygotes is determined both by heredity and parental origin; the input of other factors is possible within the individual’s reaction norm.

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Pendina, Anna A., Mikhail I. Krapivin, Yanina M. Sagurova, Irina D. Mekina, Evgeniia M. Komarova, Andrei V. Tikhonov, Arina V. Golubeva, Alexander M. Gzgzyan, Igor Yu Kogan et Olga A. Efimova. « Telomere Length in Human Spermatogenic Cells as a New Potential Predictor of Clinical Outcomes in ART Treatment with Intracytoplasmic Injection of Testicular Spermatozoa ». International Journal of Molecular Sciences 24, n^o 13 (21 juin 2023) : 10427. http://dx.doi.org/10.3390/ijms241310427.

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Predicting the clinical outcomes of intracytoplasmic sperm injection (ICSI) cycles that use the testicular spermatozoa of azoospermic patients presents a challenge. Thus, the development of additional approaches to assessing the competence of a testicular-sperm-derived embryo without causing damage to gametes or the embryo is necessary. One of the key parameters in determining such developmental competence is telomere length (TL). We aimed to analyze TLs in spermatogenic cells from the testicular biopsy samples of azoospermic patients and determine how this parameter influences embryo competence for pre- and post-implantation development. Using Q-FISH, we studied the TL of the chromosomes in spermatogonia and spermatocytes I from the TESE biopsy samples of 30 azoospermic patients. An increase in TL was detected during the differentiation from spermatogonia to spermatocytes I. The patients’ testicular spermatozoa were used in 37 ICSI cycles that resulted in 22 embryo transfers. Nine pregnancies resulted, of which, one was ectopic and eight ended in birth. The analysis of embryological outcomes revealed a dependence between embryo competence for development to the blastocyst stage and the TL in spermatogenic cells. The TLs in spermatogonia and spermatocytes I in the testicular biopsy samples were found to be higher in patients whose testicular sperm ICSI cycles resulted in a birth. Therefore, the length of telomeres in spermatogenic cells can be considered as a potential prognostic criterion in assessing the competence of testicular-sperm-derived embryos for pre- and post-implantation development. The results of this study provide the basis for the development of a laboratory test for the prediction of testicular sperm ICSI cycle outcomes.

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Darmishonnejad, Zahra, Marziyeh Tavalaee, Tayebeh Izadi, Somayeh Tanhaei et Mohammad Hossein Nasr-Esfahani. « Evaluation of sperm telomere length in infertile men with failed/low fertilization after intracytoplasmic sperm injection ». Reproductive BioMedicine Online 38, n^o 4 (avril 2019) : 579–87. http://dx.doi.org/10.1016/j.rbmo.2018.12.022.

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Vecoli, Cecilia, Luigi Montano, Andrea Borghini, Tiziana Notari, Antonino Guglielmino, Antonella Mercuri, Stefano Turchi et Maria Andreassi. « Effects of Highly Polluted Environment on Sperm Telomere Length : A Pilot Study ». International Journal of Molecular Sciences 18, n^o 8 (4 août 2017) : 1703. http://dx.doi.org/10.3390/ijms18081703.

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Torra-Massana, Marc, Montserrat Barragán, Emanuela Bellu, Rafael Oliva, Amelia Rodríguez et Rita Vassena. « Sperm telomere length in donor samples is not related to ICSI outcome ». Journal of Assisted Reproduction and Genetics 35, n^o 4 (16 janvier 2018) : 649–57. http://dx.doi.org/10.1007/s10815-017-1104-2.

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Yang, Qingling, Feifei Zhao, Shanjun Dai, Nan Zhang, Wanli Zhao, Rui Bai et Yingpu Sun. « Sperm telomere length is positively associated with the quality of early embryonic development ». Human Reproduction 30, n^o 8 (16 juin 2015) : 1876–81. http://dx.doi.org/10.1093/humrep/dev144.

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Denham, Joshua. « The association between sperm telomere length, cardiorespiratory fitness and exercise training in humans ». Biomedical Journal 42, n^o 6 (décembre 2019) : 430–33. http://dx.doi.org/10.1016/j.bj.2019.07.003.

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Aston, K. I., S. C. Hunt, E. Susser, M. Kimura, P. Factor-Litvak, D. Carrell et A. Aviv. « Divergence of sperm and leukocyte age-dependent telomere dynamics : implications for male-driven evolution of telomere length in humans ». Molecular Human Reproduction 18, n^o 11 (9 juillet 2012) : 517–22. http://dx.doi.org/10.1093/molehr/gas028.

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An, Gaole, Xingnan Zhao et Chenghui Zhao. « Unraveling the causal association between leukocyte telomere length and infertility : A two-sample Mendelian randomization study ». PLOS ONE 19, n^o 3 (21 mars 2024) : e0298997. http://dx.doi.org/10.1371/journal.pone.0298997.

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Infertility is a significant challenge in modern society, and observed studies have reported the association between telomere length and infertility. Whether this relationship is causal remains controversial.We employed two-sample mendelian randomization (MR) to investigate the causal relationship between leukocyte telomere length (LTL) and major causes of infertility, including male and female infertility, sperm abnormalities, and endometriosis. MR analyses were mainly performed using the inverse variance weighted (IVW) method and complemented with other MR methods.Our findings demonstrate a causal association between LTL and endometriosis (OR1.304, 95% CI (1.122,1.517), p = 0.001), suggesting its potential as a biomarker for this condition. However, we did not observe a significant causal relationship between LTL and other infertility causes.Our study presents compelling evidence on the relationship between LTL and endometriosis. Meanwhile, our study demonstrates that there is no causal relationship between LTL and infertility. This research contributes to the field by shedding light on the importance of LTL in the early diagnosis and intervention of endometriosis.

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Niederberger, Craig. « Re : Sperm Telomere Length is Positively Associated with the Quality of Early Embryonic Development ». Journal of Urology 195, n^o 4 Part 1 (avril 2016) : 1076–77. http://dx.doi.org/10.1016/j.juro.2016.01.031.

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Berteli, Thalita S., Fang Wang, Paula A. Navarro, Fabiana B. Kohlrausch et David L. Keefe. « LINE 1 COPY NUMBER DECREASES AND TELOMERE LENGTH INCREASES WITH AGING IN SPERM CELLS ». Fertility and Sterility 114, n^o 3 (septembre 2020) : e551. http://dx.doi.org/10.1016/j.fertnstert.2020.09.088.

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Lopes, Ana Catarina, Pedro Fontes Oliveira, Soraia Pinto, Carolina Almeida, Maria João Pinho, Rosália Sá, Eduardo Rocha, Alberto Barros et Mário Sousa. « Discordance between human sperm quality and telomere length following differential gradient separation/swim-up ». Journal of Assisted Reproduction and Genetics 37, n^o 10 (7 août 2020) : 2581–603. http://dx.doi.org/10.1007/s10815-020-01897-1.

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Yadav, Anjali, Prabhakar Tiwari et Rima Dada. « Yoga : As a Transformative Approach to Addressing Male Infertility and Enhancing Reproductive Health in Men : A Narrative Review ». Journal of Human Reproductive Sciences 17, n^o 4 (octobre 2024) : 224–31. https://doi.org/10.4103/jhrs.jhrs_147_24.

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ABSTRACT Infertility presents multifaceted challenges that encompass both physical and emotional burdens. Yoga, as a comprehensive system of mind–body medicine, serves as an effective intervention for managing male factor infertility, a complex lifestyle disorder with significant psychosomatic elements. This review explores the transformative role of yoga in addressing both the emotional and physical dimensions of infertility. By incorporating physical postures, breath control and meditation, yoga promotes emotional well-being and enhances reproductive health by improving the integrity of nuclear and mitochondrial genomes as well as the epigenome. In addition, yoga contributes to maintaining sperm telomere length through the regulation of seminal free radical levels and increased telomerase activity, which are crucial for optimal embryo cleavage and the development of high-quality blastocysts. Integrating yoga as an adjunctive therapeutic approach fosters a supportive intrauterine environment and facilitates physiological homoeostasis, thereby increasing the likelihood of successful fertilisation and implantation. Gentle asanas and flowing sequences promote relaxation, alleviate tension and cultivate emotional stability, while meditation aids in emotional healing and resilience during the infertility journey. Specific asanas, such as Baddha Konasana (bound angle pose), Bhujangasana (cobra pose) and Sarvangasana (shoulder stand), stimulate reproductive organs, enhance blood circulation and regulate hormone production. Pranayama techniques further support endocrine balance and overall vitality. Moreover, yoga provides a non-invasive strategy for managing fertility-related conditions leading to improved reproductive health and overall well-being. This review aims to elucidate the comprehensive role of yoga in improving male infertility, focusing on its impact on sperm nuclear and mitochondrial genomes, the epigenome and telomere health. In addition, it underscores the importance of self-care, open communication and shared experiences with partners. Practicing yoga regularly supports psychosocial well-being, promotes holistic healing, enhances physical and mental health and probably helps in improving reproductive health, thereby fostering resilience and self-efficacy throughout the journey of fertility and reproduction.

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Agarwal, Ashok, Manesh Kumar Panner Selvam, Luna Samanta, Sarah C. Vij, Neel Parekh, Edmund Sabanegh, Nicholas N. Tadros, Mohamed Arafa et Rakesh Sharma. « Effect of Antioxidant Supplementation on the Sperm Proteome of Idiopathic Infertile Men ». Antioxidants 8, n^o 10 (16 octobre 2019) : 488. http://dx.doi.org/10.3390/antiox8100488.

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Antioxidant supplementation in idiopathic male infertility has a beneficial effect on semen parameters. However, the molecular mechanism behind this effect has not been reported. The objective of this study was to evaluate the sperm proteome of idiopathic infertile men pre- and post-antioxidant supplementation. Idiopathic infertile men were provided with oral antioxidant supplementation once daily for a period of 6 months. Of the 379 differentially expressed proteins (DEPs) between pre- and post-antioxidant treatment patients, the majority of the proteins (n = 274) were overexpressed following antioxidant treatment. Bioinformatic analysis revealed the activation of oxidative phosphorylation pathway and upregulation of key proteins involved in spermatogenesis, sperm maturation, binding of sperm, fertilization and normal reproductive function. In addition, the transcriptional factors associated with antioxidant defense system (PPARGC1A) and free radical scavenging (NFE2L2) were predicted to be functionally activated post-treatment. Key DEPs, namely, NDUFS1, CCT3, PRKARA1 and SPA17 validated by Western blot showed significant overexpression post-treatment. Our novel proteomic findings suggest that antioxidant supplementation in idiopathic infertile men improves sperm function at the molecular level by modulating proteins involved in CREM signaling, mitochondrial function and protein oxidation. Further, activation of TRiC complex helped in nuclear compaction, maintenance of telomere length, flagella function, and expression of zona pellucida receptors for sperm–oocyte interaction.

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