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Zhang Z, Zhang J, Zhang K, Ge X, Zhai X. Robust evidence supports a causal link between higher birthweight and longer telomere length: a mendelian randomization study. Front Genet 2024; 15:1264028. [PMID: 38974386 PMCID: PMC11224456 DOI: 10.3389/fgene.2024.1264028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 05/17/2024] [Indexed: 07/09/2024] Open
Abstract
Background Observational studies have suggested a potential relationship between birthweight and telomere length. However, the causal link between these two parameters remains undefined. In this study, we use Mendelian Randomization (MR). This method employs genetic variants as instrumental variables, to explore the existence of causal associations and elucidate the causal relationship between birth weight and telomere length. Methods We used 35 single nucleotide polymorphisms (SNPs) as instrumental variables for birth weight. These SNPs were identified from a meta-analysis involving 153,781 individuals. Furthermore, we obtained summary statistics for telomere length from a study conducted on 472,174 United Kingdom Biobank participants. To evaluate the causal estimates, we applied the random effect inverse variance weighted method (IVW) and several other MR methods, such as MR-Egger, weighted median, and MR-PRESSO, to verify the reliability of our findings. Results Our analysis supports a significant causal relationship between genetically predicted birth weight and telomer3e length. The inverse variance weighted analysis results for birth weight (Beta = 0.048; 95%CI = 0.023 to 0.073; p < 0.001) corroborate this association. Conclusion Our study provides robust evidence supporting a causal link between higher birth weight and longer telomere length.
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Affiliation(s)
- Zhuoya Zhang
- Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Jiale Zhang
- Institute of Basic Theory for Chinese Medicine, China Academy of Chinese Medical Sciences, Beijing, China
| | - Kaiqi Zhang
- Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiaolei Ge
- Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing, China
| | - Xu Zhai
- Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing, China
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2
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Ju W, Zhao Y, Yu Y, Zhao S, Xiang S, Lian F. Mechanisms of mitochondrial dysfunction in ovarian aging and potential interventions. Front Endocrinol (Lausanne) 2024; 15:1361289. [PMID: 38694941 PMCID: PMC11061492 DOI: 10.3389/fendo.2024.1361289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Accepted: 03/22/2024] [Indexed: 05/04/2024] Open
Abstract
Mitochondria plays an essential role in regulating cellular metabolic homeostasis, proliferation/differentiation, and cell death. Mitochondrial dysfunction is implicated in many age-related pathologies. Evidence supports that the dysfunction of mitochondria and the decline of mitochondrial DNA copy number negatively affect ovarian aging. However, the mechanism of ovarian aging is still unclear. Treatment methods, including antioxidant applications, mitochondrial transplantation, emerging biomaterials, and advanced technologies, are being used to improve mitochondrial function and restore oocyte quality. This article reviews key evidence and research updates on mitochondrial damage in the pathogenesis of ovarian aging, emphasizing that mitochondrial damage may accelerate and lead to cellular senescence and ovarian aging, as well as exploring potential methods for using mitochondrial mechanisms to slow down aging and improve oocyte quality.
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Affiliation(s)
- Wenhan Ju
- The First Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yuewen Zhao
- CReATe Fertility Centre, Toronto, ON, Canada
| | - Yi Yu
- Department of Reproduction and Genetics, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Shuai Zhao
- The First Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Shan Xiang
- The First Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Fang Lian
- Department of Reproduction and Genetics, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
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3
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Córdova-Oriz I, Polonio AM, Cuadrado-Torroglosa I, Chico-Sordo L, Medrano M, García-Velasco JA, Varela E. Chromosome ends and the theory of marginotomy: implications for reproduction. Biogerontology 2024; 25:227-248. [PMID: 37943366 DOI: 10.1007/s10522-023-10071-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/21/2023] [Indexed: 11/10/2023]
Abstract
Telomeres are the protective structures located at the ends of linear chromosomes. They were first described in the 1930s, but their biology remained unexplored until the early 70s, when Alexey M. Olovnikov, a theoretical biologist, suggested that telomeres cannot be fully copied during DNA replication. He proposed a theory that linked this phenomenon with the limit of cell proliferation capacity and the "duration of life" (theory of marginotomy), and suggested a potential of telomere lenghthening for the prevention of aging (anti-marginotomy). The impact of proliferative telomere shortening on life expectancy was later confirmed. In humans, telomere shortening is counteracted by telomerase, an enzyme that is undetectable in most adult somatic cells, but present in cancer cells and adult and embryonic stem and germ cells. Although telomere length dynamics are different in male and female gametes during gametogenesis, telomere lengths are reset at the blastocyst stage, setting the initial length of the species. The role of the telomere pathway in reproduction has been explored for years, mainly because of increased infertility resulting from delayed childbearing. Short telomere length in ovarian somatic cells is associated to decreased fertility and higher aneuploidy rates in embryos. Consequently, there is a growing interest in telomere lengthening strategies, aimed at improving fertility. It has also been observed that lifestyle factors can affect telomere length and improve fertility outcomes. In this review, we discuss the implications of telomere theory in fertility, especially in oocytes, spermatozoa, and embryos, as well as therapies to enhance reproductive success.
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Affiliation(s)
- Isabel Córdova-Oriz
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Alba M Polonio
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Isabel Cuadrado-Torroglosa
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Lucía Chico-Sordo
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Marta Medrano
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Juan A García-Velasco
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
- IVIRMA Global Research Alliance, IVIRMA Madrid, Madrid, Spain
- Department of Medical Specialties and Public Health, Edificio Departamental II, Rey Juan Carlos University, Av. de Atenas, s/n, 28922, Alcorcón, Madrid, Spain
| | - Elisa Varela
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain.
- Department of Medical Specialties and Public Health, Edificio Departamental II, Rey Juan Carlos University, Av. de Atenas, s/n, 28922, Alcorcón, Madrid, Spain.
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4
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Huang M, Wang Y, Fang L, Liu C, Feng F, Liu L, Sun C. T cell senescence: a new perspective on immunotherapy in lung cancer. Front Immunol 2024; 15:1338680. [PMID: 38415245 PMCID: PMC10896971 DOI: 10.3389/fimmu.2024.1338680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/30/2024] [Indexed: 02/29/2024] Open
Abstract
T cell senescence is an indication of T cell dysfunction. The ability of senescent T cells to respond to cognate antigens is reduced and they are in the late stage of differentiation and proliferation; therefore, they cannot recognize and eliminate tumor cells in a timely and effective manner, leading to the formation of the suppressive tumor microenvironment. Establishing methods to reverse T cell senescence is particularly important for immunotherapy. Aging exacerbates profound changes in the immune system, leading to increased susceptibility to chronic, infectious, and autoimmune diseases. Patients with malignant lung tumors have impaired immune function with a high risk of recurrence, metastasis, and mortality. Immunotherapy based on PD-1, PD-L1, CTLA-4, and other immune checkpoints is promising for treating lung malignancies. However, T cell senescence can lead to low efficacy or unsuccessful treatment results in some immunotherapies. Efficiently blocking and reversing T cell senescence is a key goal of the enhancement of tumor immunotherapy. This study discusses the characteristics, mechanism, and expression of T cell senescence in malignant lung tumors and the treatment strategies.
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Affiliation(s)
- Mengge Huang
- College of First Clinical Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yuetong Wang
- College of First Clinical Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Liguang Fang
- College of First Clinical Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Cun Liu
- College of Traditional Chinese Medicine, Weifang Medical University, Weifang, China
| | - Fubin Feng
- Department of Oncology, Weifang Traditional Chinese Hospital, Weifang, China
| | - Lijuan Liu
- Department of Oncology, Weifang Traditional Chinese Hospital, Weifang, China
| | - Changgang Sun
- College of Traditional Chinese Medicine, Weifang Medical University, Weifang, China
- Department of Oncology, Weifang Traditional Chinese Hospital, Weifang, China
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5
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Knight AK, Spencer JB, Smith AK. DNA methylation as a window into female reproductive aging. Epigenomics 2024; 16:175-188. [PMID: 38131149 PMCID: PMC10841041 DOI: 10.2217/epi-2023-0298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
People with ovaries experience reproductive aging as their reproductive function and system declines. This has significant implications for both fertility and long-term health, with people experiencing an increased risk of cardiometabolic disorders after menopause. Reproductive aging can be assessed through markers of ovarian reserve, response to fertility treatment or molecular biomarkers, including DNA methylation. Changes in DNA methylation with age associate with poorer reproductive outcomes, and epigenome-wide studies can provide insight into genes and pathways involved. DNA methylation-based epigenetic clocks can quantify biological age in reproductive tissues and systemically. This review provides an overview of hallmarks and theories of aging in the context of the reproductive system, and then focuses on studies of DNA methylation in reproductive tissues.
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Affiliation(s)
- Anna K Knight
- Research Division, Department of Gynecology & Obstetrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jessica B Spencer
- Reproductive Endocrinology & Infertility Division, Department of Gynecology & Obstetrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Alicia K Smith
- Research Division, Department of Gynecology & Obstetrics, Emory University School of Medicine, Atlanta, GA 30322, USA
- Reproductive Endocrinology & Infertility Division, Department of Gynecology & Obstetrics, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Psychiatry & Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA
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Han X, Wu T, Liu CY. Univariable and multivariable Mendelian randomization investigating the effects of telomere length on the risk of adverse pregnancy outcomes. Front Endocrinol (Lausanne) 2023; 14:1225600. [PMID: 37600718 PMCID: PMC10435990 DOI: 10.3389/fendo.2023.1225600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
Background Numerous observational studies have revealed a correlation between telomere length (TL) and adverse pregnancy outcomes (APOs). However, the impacts of TL on APOs are still unclear. Methods Mendelian randomization (MR) was carried out using summary data from genome-wide association studies (GWAS). Inverse variance weighted (IVW) was employed as the primary analysis to explore the causal relationship between TL and APOs. The exposure data came from a GWAS dataset of IEU analysis of the United Kingdom Biobank phenotypes consisting of 472,174 European participants. Summary-level data for five APOs were obtained from the GWAS datasets of the FinnGen consortium. We also performed multivariate MR (MVMR), adjusting for smoking, alcohol intake, body mass index (BMI), and number of live births. In addition, we conducted a series of rigorous analyses to further examine the validity of our MR findings. Results After Bonferroni correction and rigorous quality control, univariable MR (UVMR) demonstrated that a shorter TL was significantly associated with an increased risk of spontaneous abortion (SA) (odds ratio [OR]: 0.815; 95% confidence interval [CI]: 0.714-0.930; P = 0.002) and preterm birth (PTB) (OR: 0.758; 95% CI: 0.632-0.908; P = 0.003) in the IVW model. There was a nominally significant relationship between TL and preeclampsia (PE) in the IVW model (OR: 0.799; 95% CI: 0.651-0.979; P = 0.031). However, no significant association was found between TL and gestational diabetes mellitus (GDM) (OR: 0.950; 95% CI: 0.804-1.122; P = 0.543) or fetal growth restriction (FGR) (OR: 1.187; 95% CI: 0.901-1.565; P = 0.223) among the five statistical models. Furthermore, we did not find a significant causal effect of APOs on TL in the reverse MR analysis. MVMR analysis showed that the causal effects of TL on SA remained significant after accounting for smoking, alcohol intake, BMI, and number of live births. Conclusion Our MR study provides robust evidence that shorter telomeres were associated with an increased risk of SA. Further work is necessary to investigate the potential mechanisms. UVMR and MVMR findings showed limited evidence that TL affects the risk of PTB, PE, GDM, and FGR, illustrating that the outcomes of previous observational studies may have been confounded.
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Affiliation(s)
- Xinyu Han
- Department of First Clinical Medical College, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Tianqiang Wu
- Department of First Clinical Medical College, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Chun yan Liu
- Department of Endocrinology, The First Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, China
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7
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Córdova-Oriz I, Kohls G, Iglesias C, Polonio AM, Chico-Sordo L, Toribio M, Meseguer M, Varela E, Pellicer A, García-Velasco JA. A Randomized Controlled Intervention Trial with Danazol to Improve Telomeric and Fertility Parameters in Women with Diminished Ovarian Reserve: A Pilot Study. WOMEN'S HEALTH REPORTS (NEW ROCHELLE, N.Y.) 2023; 4:305-318. [PMID: 37476605 PMCID: PMC10354732 DOI: 10.1089/whr.2023.0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 06/07/2023] [Indexed: 07/22/2023]
Abstract
Background Most women who are treated at in vitro fertilization (IVF) clinics have trouble conceiving due to ovarian failure (OF), which seems to be associated to short telomeres and reduced or absent telomerase activity in their granulosa cells. Indeed, telomere pathways are involved in organ dysfunction. However, sexual steroids can stimulate the expression of the telomerase gene and have been successfully used to prevent telomere attrition. Thus, a strategy to improve IVF outcomes in women with OF could be telomerase reactivation using sexual steroids. Methods We conducted a double-blind, placebo-controlled study. Patients with diminished ovarian reserve were randomized to Danazol or placebo for 3 months. We included patients with normal ovarian reserve in the study as untreated controls. Patients and controls underwent several ovarian stimulations (OSs). Telomere and IVF parameters were assessed. Results We found that the mean telomere length in blood and the percentage of short and long telomeres were similar throughout the 3 months of treatment with Danazol. Remarkably, while the number of cells with one telomeric repeat-containing RNA (TERRA) focus decreased (p = 0.04) after the first month of Danazol treatment, the number of cells with 2 to 4 TERRA foci increased (p = 0.02). Regarding fertility, no differences were found in the antral follicle count. Interestingly, in OS performed after the trial, all Danazol-treated patients had a better MII oocyte rate compared to OS performed before the pilot study.EudraCT number: 2018-004400-19. Conclusions Danazol treatment seemed to affect telomere maintenance, since both the number of TERRA foci and the ratio of MII oocytes changed. However, further research is needed to confirm these results.
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Affiliation(s)
- Isabel Córdova-Oriz
- The Health Research Institute La Fe (IIS La Fe), IVI Foundation, Valencia, Spain
| | | | | | - Alba M. Polonio
- The Health Research Institute La Fe (IIS La Fe), IVI Foundation, Valencia, Spain
| | - Lucía Chico-Sordo
- The Health Research Institute La Fe (IIS La Fe), IVI Foundation, Valencia, Spain
| | | | - Marcos Meseguer
- The Health Research Institute La Fe (IIS La Fe), IVI Foundation, Valencia, Spain
- Laboratory of In Vitro Fertilization, IVIRMA Valencia, Valencia, Spain
| | - Elisa Varela
- The Health Research Institute La Fe (IIS La Fe), IVI Foundation, Valencia, Spain
- Department of Medical Specialties and Public Health, Rey Juan Carlos University, Madrid, Spain
| | - Antonio Pellicer
- The Health Research Institute La Fe (IIS La Fe), IVI Foundation, Valencia, Spain
- School of Medicine, Department of Obstetrics and Gynecology, University of Valencia, Valencia, Spain
- IVIRMA Rome, Rome, Italy
| | - Juan A. García-Velasco
- The Health Research Institute La Fe (IIS La Fe), IVI Foundation, Valencia, Spain
- IVIRMA Madrid, Madrid, Spain
- Department of Medical Specialties and Public Health, Rey Juan Carlos University, Madrid, Spain
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8
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Polonio AM, Medrano M, Chico-Sordo L, Córdova-Oriz I, Cozzolino M, Montans J, Herraiz S, Seli E, Pellicer A, García-Velasco JA, Varela E. Impaired telomere pathway and fertility in Senescence-Accelerated Mice Prone 8 females with reproductive senescence. Aging (Albany NY) 2023; 15:4600-4624. [PMID: 37338562 DOI: 10.18632/aging.204731] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 05/04/2023] [Indexed: 06/21/2023]
Abstract
Ovarian aging is the main cause of infertility and telomere attrition is common to both aging and fertility disorders. Senescence-Accelerated Mouse Prone 8 (SAMP8) model has shortened lifespan and premature infertility, reflecting signs of reproductive senescence described in middle-aged women. Thus, our objective was to study SAMP8 female fertility and the telomere pathway at the point of reproductive senescence. The lifespan of SAMP8 and control mice was monitored. Telomere length (TL) was measured by in situ hybridization in blood and ovary. Telomerase activity (TA) was analyzed by telomere-repeat amplification protocol, and telomerase expression, by real-time quantitative PCR in ovaries from 7-month-old SAMP8 and controls. Ovarian follicles at different stages of maturation were evaluated by immunohistochemistry. Reproductive outcomes were analyzed after ovarian stimulation. Unpaired t-test or Mann-Whitney test were used to calculate p-values, depending on the variable distribution. Long-rank test was used to compare survival curves and Fisher's exact test was used in contingency tables. Median lifespan of SAMP8 females was reduced compared to SAMP8 males (p = 0.0138) and control females (p < 0.0001). In blood, 7-month-old SAMP8 females presented lower mean TL compared to age-matched controls (p = 0.041). Accordingly, the accumulation of short telomeres was higher in 7-month-old SAMP8 females (p = 0.0202). Ovarian TA was lower in 7-month-old SAMP8 females compared to controls. Similarly, telomerase expression was lower in the ovaries of 7-month-old SAMP8 females (p = 0.04). Globally, mean TL in ovaries and granulosa cells (GCs) were similar. However, the percentage of long telomeres in ovaries (p = 0.004) and GCs (p = 0.004) from 7-month-old SAMP8 females was lower compared to controls. In early-antral and antral follicles, mean TL of SAMP8 GCs was lower than in age-matched controls (p = 0.0156 for early-antral and p = 0.0037 for antral follicles). Middle-aged SAMP8 showed similar numbers of follicles than controls, although recovered oocytes after ovarian stimulation were lower (p = 0.0068). Fertilization rate in oocytes from SAMP8 was not impaired, but SAMP8 mice produced significantly more morphologically abnormal embryos than controls (27.03% in SAMP8 vs. 1.22% in controls; p < 0.001). Our findings suggest telomere dysfunction in SAMP8 females, at the time of reproductive senescence.
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Affiliation(s)
- Alba M Polonio
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
| | - Marta Medrano
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
| | - Lucía Chico-Sordo
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
| | - Isabel Córdova-Oriz
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
| | | | | | - Sonia Herraiz
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
| | - Emre Seli
- IVIRMA New Jersey, Basking Ridge, NJ 07920, USA
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Heaven, CT 06510, USA
| | - Antonio Pellicer
- IVIRMA Rome, Rome, Italy
- Department of Pediatrics, Obstetrics and Gynecology, University of Valencia, Valencia, Spain
| | - Juan A García-Velasco
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
- IVIRMA Madrid, Madrid, Spain
- Department of Obstetrics and Gynecology, Rey Juan Carlos University, Madrid, Spain
| | - Elisa Varela
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
- Department of Obstetrics and Gynecology, Rey Juan Carlos University, Madrid, Spain
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Chieffi Baccari G, Iurato G, Santillo A, Dale B. Male Germ Cell Telomeres and Chemical Pollutants. Biomolecules 2023; 13:biom13050745. [PMID: 37238614 DOI: 10.3390/biom13050745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/20/2023] [Accepted: 04/24/2023] [Indexed: 05/28/2023] Open
Abstract
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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Affiliation(s)
- Gabriella Chieffi Baccari
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università della Campania "Luigi Vanvitelli", 81100 Caserta, Italy
| | | | - Alessandra Santillo
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università della Campania "Luigi Vanvitelli", 81100 Caserta, Italy
| | - Brian Dale
- Centro Fecondazione Assistita (CFA-Italia), 80127 Napoli, Italy
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10
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Portillo AM, Varela E, García-Velasco JA. Influence of telomerase activity and initial distribution on human follicular aging: Moving from a discrete to a continuum model. Math Biosci 2023; 358:108985. [PMID: 36828232 DOI: 10.1016/j.mbs.2023.108985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 02/15/2023] [Accepted: 02/15/2023] [Indexed: 02/24/2023]
Abstract
A discrete model is proposed for the temporal evolution of a population of cells sorted according to their telomeric length. This model assumes that, during cell division, the distribution of the genetic material to daughter cells is asymmetric, i.e. chromosomes of one daughter cell have the same telomere length as the mother, while in the other daughter cell telomeres are shorter. Telomerase activity and cell death are also taken into account. The continuous model is derived from the discrete model by introducing the generational age as a continuous variable in [0,h], being h the Hayflick limit, i.e. the number of times that a cell can divide before reaching the senescent state. A partial differential equation with boundary conditions is obtained. The solution to this equation depends on the initial telomere length distribution. The initial and boundary value problem is solved exactly when the initial distribution is of exponential type. For other types of initial distributions, a numerical solution is proposed. The model is applied to the human follicular growth from preantral to preovulatory follicle as a case study and the aging rate is studied as a function of telomerase activity, the initial distribution and the Hayflick limit. Young, middle and old cell-aged initial normal distributions are considered. In all cases, when telomerase activity decreases, the population ages and the smaller the h value, the higher the aging rate becomes. However, the influence of these two parameters is different depending on the initial distribution. In conclusion, the worst-case scenario corresponds to an aged initial telomere distribution.
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Affiliation(s)
- A M Portillo
- Instituto de Investigación en Matemáticas de la Universidad de Valladolid, Valladolid, Spain; Departamento de Matemática Aplicada, Escuela de Ingenierías Industriales, Universidad de Valladolid, Pso. Prado de la Magdalena 3-5, Valladolid, 47011, Spain.
| | - E Varela
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Edificio Biopolo. Av. Fernando Abril Martorell, 106 - Torre A, Planta 1, Valencia, 46026, Spain; Rey Juan Carlos University, Edificio Departamental II. Av. de Atenas, s/n, Alcorcón, Madrid, 28922, Spain.
| | - J A García-Velasco
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Edificio Biopolo. Av. Fernando Abril Martorell, 106 - Torre A, Planta 1, Valencia, 46026, Spain; IVIRMA Madrid, Av. del Talgo, 68, Madrid, 28023, Spain; Rey Juan Carlos University, Edificio Departamental II. Av. de Atenas, s/n, Alcorcón, Madrid, 28922, Spain.
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11
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Resveratrol and SIRT1: Antiaging Cornerstones for Oocytes? Nutrients 2022; 14:nu14235101. [PMID: 36501130 PMCID: PMC9736670 DOI: 10.3390/nu14235101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022] Open
Abstract
It is well-known that there is an enormous variability in the aging-related decline of oocytes' quantity and their developmental competence among mammalian species. The implication of female germline aging is profound from the perspective of evolutionary conservation of the aging mechanism, a topic of continuous and widespread interest that has yet to be fully addressed for the mammalian oocyte. There is a certain need to develop novel antiaging strategies to delay or slow down aging, or even to reverse the aging phenotype in the oocyte. In the past two decades, several antioxidants have been tested for this purpose. Resveratrol is one of these latter-mentioned compounds, which has shown anti-inflammatory and antiaging properties in a dose-dependent manner. Interestingly, resveratrol appears to enhance the activity of so-called Sirtuin 1, too. Therefore, the aim of this review is to summarize and discuss the latest findings related to resveratrol, Sirtuin 1, and their crosstalk and influence on the mammalian oocyte to elucidate the question of whether these factors can delay or slow down reproductive aging.
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