Mitochondrial SIRT3 and its target glutamate dehydrogenase are altered in follicular cells of women with reduced ovarian reserve or advanced maternal age

STUDY QUESTION: Is the activity of sirtuin 3 (SIRT3) altered in granulosa and cumulus cells from young women with reduced ovarian reserve or women of advanced maternal age? SUMMARY ANSWER: SIRT3 mRNA and active protein in granulosa and cumulus cells were decreased in women with reduced ovarian reserve and advanced maternal age. WHAT IS KNOWN ALREADY: Young women with reduced ovarian reserve or women of advanced maternal age have reduced oocyte viability, possibly due to altered granulosa and cumulus cell metabolism. The mitochondrial SIRT3 protein may be implicated in these processes as it is able to sense the metabolic state of the cell and alter mitochondrial protein function post-translationally. STUDY DESIGN, SIZE, DURATION: This is a prospective cohort study, in which women (n = 72) undergoing routine IVF/ICSI were recruited and allocated to one of three cohorts based on age and ovarian reserve (as assessed by serum anti-Mullerian hormone level). Women were classified as young (≤35 years) or of advanced maternal age (≥40 years). PARTICIPANTS/MATERIALS, SETTING, METHODS: Granulosa and cumulus cells were collected. SIRT3 mRNA and protein levels and protein activity was analysed in granulosa and cumulus cells via quantitative PCR, immunohistochemistry and western blotting, and deacetylation activity, respectively. Activity of the glutamate dehydrogenase (GDH) enzyme, a known target of SIRT3, was assessed, and acetylated proteins in mitochondria isolated from granulosa and cumulus cells were separated by immunoprecipitation and acetylation of GDH assessed by western blotting. Data for women with good prognosis (young women with normal ovarian reserve) were compared with those from young women with reduced ovarian reserve and those of advanced maternal age. MAIN RESULTS AND THE ROLE OF CHANCE: SIRT3 mRNA and active protein were present in granulosa and cumulus cells and co-localized to the mitochondria. SIRT3 mRNA in granulosa cells was decreased in young women with reduced ovarian reserve and advanced maternal age versus young women with normal ovarian reserve (P < 0.05). SIRT3 mRNA in cumulus cells was decreased in women of advanced maternal age versus young women with normal ovarian reserve only (P < 0.05). Granulosa cell GDH activity was decreased in young women with reduced ovarian reserve and in women of advanced maternal age (P < 0.05), whereas cumulus cell GDH activity was reduced in the advanced maternal age group only (P < 0.05). The acetylation profile of GDH in mitochondria revealed increased acetylation of GDH in granulosa and cumulus cells from women of advanced maternal age (P < 0.05) while young women with reduced ovarian reserve had increased GDH acetylation in granulosa cells only (P < 0.05). LIMITATIONS, REASONS FOR CAUTION: Although patients were allocated to groups based on maternal age and ovarian reserve and matched for BMI, other maternal factors may also alter the 'molecular health' of ovarian cells. WIDER IMPLICATIONS OF THE FINDINGS: Our data suggest that SIRT3 post-translational modification of mitochondrial enzymes in human granulosa and cumulus cells may regulate GDH activity, thus altering the metabolic milieu surrounding the developing oocyte. Owing to the association between the decline in oocyte quality and pregnancy rates in women of advanced maternal age and the possible association with reduced ovarian reserve, knowledge of perturbed SIRT3 function in granulosa and cumulus cells may lead to novel therapies to improve mitochondrial metabolism in the oocyte and follicular cells in women undergoing IVF treatment. STUDY FUNDING/COMPETING INTEREST(S): No conflicts of interest to declare. Research was funded by an NHMRC project grant.L. Pacella-Ince, D.L Zander-Fox, and M. Lan

Comparison of in vitro fertilisation/intracytoplasmic sperm injection on live birth rates in couples with non-male factor infertility and advanced maternal age

Published: 07 January 2021. Corrected by: Correction to: Comparison of in vitro fertilisation/intracytoplasmic sperm injection on live birth rates in couples with non-male factor infertility and advanced maternal age, in Vol. 38, Issue 3, 679. The original article unfortunately contained a mistake in the first line of the Conclusion section.PURPOSE: To determine if the use of ICSI in women of advanced maternal age with non-male factor infertility increases chances of live birth. METHODS: Retrospective data analysis of 10 years of cycle data from a single Australian IVF clinic (Repromed). First cycle patients only of an advanced maternal age (≥ 35 years) with non-male factor infertility utilising standard IVF or ICSI insemination and having at least three oocytes collected at egg pick up were assessed for live birth following transfer of single genetically unscreened blastocyst (N = 577). Subanalysis of clinical pregnancy, miscarriage, fertilisation, embryo utilisation rate and having a blastocyst for transfer were considered. Unadjusted, covariate adjusted and propensity score weighted analysis were performed. RESULTS: The use of standard IVF insemination in women ≥ 35 years with non-male factor infertility increased the chance of a live birth compared with ICSI insemination (unadjusted OR = 2.72, 95% CI [1.78, 4.17]; adjusted OR = 2.64, 95% CI [1.64, 4.27] and weighted OR = 2.26, 95% CI [1.72, 2.98] 31% vs 14%). All other outcomes (fertilisation rate, embryo utilisation, blastocyst for embryo transfer and miscarriage rate) were unaffected. CONCLUSION: In couples with advanced maternal age and non-male factor infertility, standard IVF insemination appears to increase the chance of a live birth compared with ICSI. As such, the results of this study support the use of routine IVF as the preferred insemination technique for older women in non-male factor infertility. However, future randomised controlled trials are still required to assess this policy.Nicole O. McPherson, Andrew D. Vincent, Leanne Pacella-Ince and Kelton Tremelle

Comparison of in vitro fertilisation/intracytoplasmic sperm injection on live birth rates in couples with non-male factor infertility and advanced maternal age: overlooked details-response from authors

Letter to the EditorAbstract not available.Kelton Tremellen, Andrew D. Vincent, Leanne Pacella-Ince, Nicole O. McPherso

Reactive oxygen species in the mammalian pre-implantation embryo

Reactive oxygen species (ROS) occur naturally in pre-implantation embryos as a by-product of ATP generation through oxidative phosphorylation and enzymes such as NADPH oxidase and xanthine oxidase. Biological concentrations of ROS are required for crucial embryonic events such as pronuclear formation, first cleavage and cell proliferation. However, high concentrations of ROS are detrimental to embryo development, resulting in embryo arrest, increased DNA damage and modification of gene expression leading to aberrant fetal growth and health. In vivo embryos are protected against oxidative stress by oxygen scavengers present in follicular and oviductal fluids, while in vitro, embryos rely on their own antioxidant defence mechanisms to protect against oxidative damage, including superoxide dismutase, catalase, glutathione and glutamylcysteine synthestase. Pre-implantation embryonic ROS originate from eggs, sperm and embryos themselves or from the external environment (i.e. in vitro culture system, obesity and ageing). This review examines the biological and pathological roles of ROS in the pre-implantation embryo, maternal and paternal origins of embryonic ROS, and from a clinical perspective, we comment on the growing interest in combating increased oxidative damage in the pre-implantation embryo through the addition of antioxidants.Joshua C Deluao, Yasmyn Winstanley, Rebecca L Robker, Leanne Pacella-Ince, Macarena B Gonzalez, and Nicole O McPherso

PIEZO-ICSI increases fertilization rates compared with standard ICSI: a prospective cohort study

Abstract Research question Is PIEZO-intracytoplasmic sperm injection (ICSI) coupled with a new novel operational fluid (perfluoro-n-octane) superior to standard ICSI? Design A cohort of patients ( n = 69) undertaking microinjection were recruited between January and November 2019 and were then prospectively case-matched. Patients required six or more mature oocytes for inclusion in the study. PIEZO-ICSI uses high-speed microinjection drilling to penetrate the zona and oolemma and deposit the spermatozoa into the cytoplasm, compared with the traditional ‘cutting’ action of ICSI. The primary outcome was fertilization, with secondary outcomes including oocyte degeneration, abnormal fertilization, embryo cryopreservation and embryo utilization. Results PIEZO-ICSI resulted in significantly higher fertilization rates (80.5 ± 2.4% vs 65.8 ± 2.3%, P < 0.0001) and lower oocyte degeneration rates (4.4 ± 1.3% vs 8.6 ± 1.2%, P = 0.019) and abnormal fertilization rates (2.9 ± 1.1% vs 7.4 ± 1.1%; P = 0.003) compared with standard ICSI. This improvement in fertilization was of most benefit in patients aged ≥38 years. This increase in fertilization increased the number of good quality embryos that were available for cryopreservation/transfer (3.8 ± 0.2 vs 3.1 ± 0.2; P = 0.038), such that patients on average had one extra usable embryo per cycle compared with standard ICSI. There were no differences to Day 5 embryo development or clinical pregnancy from fresh embryo transfer (57.1% PIEZO-ICSI vs 60.0% ICSI) between microinjection methods, although pregnancy outcomes were underpowered. Conclusions PIEZO-ICSI significantly increased fertilization rates, thereby increasing the number of embryos available for cryopreservation compared with standard ICSI. Further prospective studies assessing cumulative pregnancy rates are warranted.Deirdre Zander-Fox, Kevin Lam, Leanne Pacella-Ince, Cathy Tully, Hamish Hamilton, Kenichiro Hiraoka, Nicole O McPherson, Kelton Tremelle

Mitochondrial SIRT5 is present in follicular cells and is altered by reduced ovarian reserve and advanced maternal age

Women with reduced ovarian reserve or advanced maternal age have an altered metabolic follicular microenvironment. As sirtuin 5 (SIRT5) senses cellular metabolic state and post-translationally alters protein function, its activity may directly impact on oocyte viability and pregnancy outcome. Therefore, we investigated the role of SIRT5 in relation to ovarian reserve and maternal age. Women (n=47) undergoing routine IVF treatment were recruited and allocated to one of three cohorts based on ovarian reserve and maternal age. Surplus follicular fluid, granulosa and cumulus cells were collected. SIRT5 mRNA, protein and protein activity was confirmed in granulosa and cumulus cells via qPCR, immunohistochemistry, western blotting and desuccinylation activity. The presence of carbamoyl phosphate synthase I (CPS1), a target of SIRT5, was investigated by immunohistochemistry and follicular-fluid ammonium concentrations determined via microfluorometry. Women with reduced ovarian reserve or advanced maternal age had decreased SIRT5 mRNA, protein and desuccinylation activity in granulosa and cumulus cells resulting in an accumulation of follicular-fluid ammonium, presumably via alterations in activity of a SIRT5 target, CPS1, which was present in granulosa and cumulus cells. This suggests a role for SIRT5 in influencing oocyte quality and IVF outcomes.Leanne Pacella-Ince, Deirdre L. Zander-Fox and Michelle Lan