![]() ![]() ![]() ![]() 5 The telomeric C-strand is transcribed by RNA polymerase II, producing long noncoding RNAs which contain 5′-UUAGGG-3′ repeats, along with sequences that are present in the subtelomeric regions where transcription was initiated. 7 Telomere length (TL) in humans is ∼10 to 15 kb, with an attrition rate of about 70 base pairs per year 8 thus, TL is a bona fide marker for biological aging. In addition, telomeres confer identity to chromosome ends, to prevent them from being confused with DNA breaks. In mammals, telomeres consist of tandem repeats of the 5′-TTAGGG-3′ DNA sequence shaped by a protein complex called shelterin, which protects telomeres. 4 A primary cause of aging and organ dysfunction is telomere attrition, 5 which happens as cells divide, due to the fact that the DNA at the very end of the chromosome cannot be fully copied in each round of replication, resulting in gradual shortening. This is the case of women with diminished ovarian reserve (DOR), who usually respond poorly to ovarian stimulation (OS) and have below-par in vitro fertilization (IVF) outcomes. 1–3 Ovaries have a limited time window during which they are fully functional, and they start to decay at around 35 years of age, 3 with a decline in the quantity and quality of oocytes. Clin Exp Reprod Med 46:112–118.Increasingly delayed childbearing due to socioeconomic reasons is leading to natural ovarian aging and infertility problems. Īlahmar AT (2019) The impact of two doses of coenzyme Q10 on semen parameters and antioxidant status in men with idiopathic oligoasthenoteratozoospermia. Īkino N, Wada-Hiraike O, Isono W, Terao H, Honjo H, Miyamoto Y, Tanikawa M, Sone K, Hirano M, Harada M, Hirata T, Hirota Y, Koga K, Oda K, Fujii T, Osuga Y (2019) Activation of Nrf2/Keap1 pathway by oral Dimethylfumarate administration alleviates oxidative stress and age-associated infertility might be delayed in the mouse ovary. Iran J Reprod Med 12:595–600Īgarwal A, Gupta S, Sharma RK (2005) Role of oxidative stress in female reproduction. Īflatoonian A, Arabjahvani F, Eftekhar M, Sayadi M (2014) Effect of vitamin D insufficiency treatment on fertility outcomes in frozen-thawed embryo transfer cycles: a randomized clinical trial. The Author(s), under exclusive licence to Springer Nature B.V.Īchi MAV, Ravindranath N, Dym M (2000) Telomere length in male germ cells is inversely correlated with telomerase activity1. 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.Įmbryos Fertility Oocytes Spermatozoa Telomeres Therapies. It has also been observed that lifestyle factors can affect telomere length and improve fertility outcomes. Consequently, there is a growing interest in telomere lengthening strategies, aimed at improving fertility. Short telomere length in ovarian somatic cells is associated to decreased fertility and higher aneuploidy rates in embryos. The role of the telomere pathway in reproduction has been explored for years, mainly because of increased infertility resulting from delayed childbearing. 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. 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. The impact of proliferative telomere shortening on life expectancy was later confirmed. 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). Olovnikov, a theoretical biologist, suggested that telomeres cannot be fully copied during DNA replication. They were first described in the 1930s, but their biology remained unexplored until the early 70s, when Alexey M. Telomeres are the protective structures located at the ends of linear chromosomes. ![]()
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