Evidence that growth hormone can improve mitochondrial function in oocytes from aged mice

Ovarian aging: energy metabolism of oocytes

In women who are getting older, the quantity and quality of their follicles or oocytes and decline. This is characterized by decreased ovarian reserve function (DOR), fewer remaining oocytes, and lower quality oocytes. As more women choose to delay childbirth, the decline in fertility associated with age has become a significant concern for modern women. The decline in oocyte quality is a key indicator of ovarian aging. Many studies suggest that age-related changes in oocyte energy metabolism may impact oocyte quality. Changes in oocyte energy metabolism affect adenosine 5'-triphosphate (ATP) production, but how related products and proteins influence oocyte quality remains largely unknown. This review focuses on oocyte metabolism in age-related ovarian aging and its potential impact on oocyte quality, as well as therapeutic strategies that may partially influence oocyte metabolism. This research aims to enhance our understanding of age-related changes in oocyte energy metabolism, and the identification of biomarkers and treatment methods.

Gonadotropin elevation is ootoxic to ovulatory oocytes and inhibits oocyte maturation, and activin decoy receptor ActRIIB:Fc therapeutically restores maturation

BACKGROUND

Elevated FSH often occurs in women of advanced maternal age (AMA, age ≥ 35) and in infertility patients undergoing controlled ovarian stimulation (COS). There is controversy on whether high endogenous FSH contributes to infertility and whether high exogenous FSH adversely impacts patient pregnancy rates.

METHODS

The senescence-accelerated mouse-prone-8 (SAMP8) model of female reproductive aging was employed to assess the separate impacts of age and high FSH activity on the percentages (%) of viable and mature ovulated oocytes recovered after gonadotropin treatment. Young and midlife mice were treated with the FSH analog equine chorionic gonadotropin (eCG) to model both endogenous FSH elevation and exogenous FSH elevation. Previously we showed the activin inhibitor ActRIIB:Fc increases oocyte quality by preventing chromosome and spindle misalignments. Therefore, ActRIIB:Fc treatment was performed in an effort to increase % oocyte viability and % oocyte maturation.

RESULTS

The high FSH activity of eCG is ootoxic to ovulatory oocytes, with greater decreases in % viable oocytes in midlife than young mice. High FSH activity of eCG potently inhibits oocyte maturation, decreasing the % of mature oocytes to similar degrees in young and midlife mice. ActRIIB:Fc treatment does not prevent eCG ootoxicity, but it restores most oocyte maturation impeded by eCG.

CONCLUSIONS

FSH ootoxicity to ovulatory oocytes and FSH maturation inhibition pose a paradox given the well-known pro-growth and pro-maturation activities of FSH in the earlier stages of oocyte growth. We propose the FOOT Hypothesis ("FSH OoToxicity Hypothesis), that FSH ootoxicity to ovulatory oocytes comprises a new driver of infertility and low pregnancy success rates in DOR women attempting spontaneous pregnancy and in COS/IUI patients, especially AMA women. We speculate that endogenous FSH elevation also contributes to reduced fecundity in these DOR and COS/IUI patients. Restoration of oocyte maturation by ActRIB:Fc suggests that activin suppresses oocyte maturation in vivo. This contrasts with prior studies showing activin A promotes oocyte maturation in vitro. Improved oocyte maturation with agents that decrease endogenous activin activity with high specificity may have therapeutic benefit for COS/IVF patients, COS/IUI patients, and DOR patients attempting spontaneous pregnancies.

Ultra-Fast Vitrification: Minimizing the Toxicity of Cryoprotective Agents and Osmotic Stress in Mouse Oocyte Cryopreservation

Globally, women have been adopting oocyte cryopreservation (OC) for fertility preservation for various reasons, such as inevitable gonadotoxic treatment for specific pathologic states and social preferences. While conventional vitrification (C-VIT) has improved the success rate of OC, challenges of possible toxicities of high-concentration cryoprotective agents and osmotic stress persist. To overcome these challenges, we evaluated the ultra-fast vitrification (UF-VIT) method, which reduces the equilibration solution stage exposure time compared to C-VIT by observing mouse oocyte intracellular organelles and embryonic development. Consequently, compared to fresh mouse oocytes, UF-VIT presented significant differences only in endoplasmic reticulum (ER) intensity and mitochondrial (MT) distribution. Meanwhile, C-VIT showed substantial differences in the survival rate, key ER and MT parameters, and embryonic development rate. UF-VIT exhibited considerably fewer negative effects on key MT parameters and resulted in a notably higher blastocyst formation rate than C-VIT. Meiotic spindle (spindle and chromosomes) morphology showed no significant changes between the groups during vitrification/warming (VW), suggesting that VW did not negatively affect the meiotic spindle of the oocytes. In conclusion, UF-VIT seems more effective in OC owing to efficient cytoplasmic water molecule extraction, osmotic stress reduction, and minimization of cell contraction and expansion amplitude, thus compensating for the drawbacks of C-VIT.

NAMPT regulates mitochondria function and lipid metabolism during porcine oocyte maturation

Oocyte maturation defect can lead to maternal reproduction disorder. NAMPT is a rate-limiting enzyme in mammalian NAD+ biosynthesis pathway, which can regulate a variety of cellular metabolic processes including glucose metabolism and DNA damage repair. However, the function of NAMPT in porcine oocytes remains unknown. In this study, we showed that NAMPT involved into multiple cellular events during oocyte maturation. NAMPT expressed during all stages of porcine oocyte meiosis, and inhibition of NAMPT activity caused the cumulus expansion and polar body extrusion defects. Mitochondrial dysfunction was observed in NAMPT-deficient porcine oocytes, which showed decreased membrane potential, ATP and mitochondrial DNA content, increased oxidative stress level and apoptosis. We also found that NAMPT was essential for spindle organization and chromosome arrangement based on Ac-tubulin. Moreover, lack of NAMPT activity caused the increase of lipid droplet and affected the imbalance of lipogenesis and lipolysis. In conclusion, our study indicated that lack of NAMPT activity affected porcine oocyte maturation through its effects on mitochondria function, spindle assembly and lipid metabolism.

Growth hormone treatment improves the development of follicles and oocytes in prepubertal lambs

BACKGROUND

When prepubertal lambs are superovulated, the ovarian response to gonadotropin stimulation has great individual difference and the collected oocytes have lower developmental ability than that of adult ewes. Over the years, growth hormone (GH) has been used in assisted reproduction because it can improve the reproductive performance in humans and animals. However, the effect of GH on ovaries and oocytes of prepubertal lambs remains unclear.

METHODS

Before and during follicle-stimulating hormone (FSH) superovulation of prepubertal lambs (4‒6-week-old), the lambs were treated with high (50 mg) or low dose (25 mg) of ovine GH in a long (5 days) or short (2 days) period. The recovered oocytes were used for in vitro maturation and fertilization, and several parameters of oocyte quality and development capacity were evaluated. The possible underlying mechanisms of GH action were explored by analysis of granulosa cell (GC) transcriptome, ovarian proteome and follicular fluid metabolome.

RESULTS

Treatment of lambs with 50 mg GH over 5 days (long treatment) potentially promoted the response of lambs to superovulation and improved the development capacity of retrieved oocytes, consequently increasing the high quality embryo yield from lambs. A number of differently expressed genes or proteins were found in ovaries between GH-treated and untreated lambs. Cellular experiments revealed that GH reduced the oxidative stress of GCs and promoted the GC proliferation probably through activation of the PI3K/Akt signaling pathway. Finally, analysis of follicular fluid metabolome indicated that GH treatment altered the abundance of many metabolites in follicular fluid, such as antioxidants and fatty acids.

CONCLUSIONS

GH treatment has a beneficial role on function of lamb ovaries, which supports the development of follicles and oocytes and improves the efficiency of embryo production from prepubertal lambs.

Growth hormone reduces aneuploidy and improves oocytes quality by JAK2-MAPK3/1 pathway in aged mice

BACKGROUND

The global delay in women's reproductive age has raised concerns about age-related infertility. The decline in oocyte quality is a limiting factor of female fertility, yet there are currently no strategies to preserve oocyte quality in aged women. Here, we investigated the effects of growth hormone (GH) supplementation on aneuploidy of aged oocytes.

METHODS

For the in vivo experiments, the aged mice (8-month-old) were intraperitoneally injected with GH daily for 8 weeks. For the in vitro experiments, germinal vesicle oocytes from aged mice were treated with GH during oocyte maturation. The impacts of GH on ovarian reserve before superovulation was evaluated. Oocytes were retrieved to assess oocyte quality, aneuploidy and developmental potential characteristics. Quantitative proteomics analysis was applied to investigate the potential targets of GH in aged oocytes.

RESULTS

In this study, we demonstrated that GH supplementation in vivo not only alleviated the decline in oocyte number caused by aging, but also improved the quality and developmental potential of aged oocytes. Strikingly, we discovered that GH supplementation reduced aneuploidy in aged oocytes. Mechanically, in addition to improving mitochondrial function, our proteomic analysis indicated that the MAPK3/1 pathway may be involved in the reduction in aneuploidy of aged oocytes, as confirmed both in vivo and in vitro. In addition, JAK2 may also act as a mediator in how GH regulates MAPK3/1.

CONCLUSIONS

In conclusion, our research reveals that GH supplementation protects oocytes against aging-related aneuploidy and enhances the quality of aged oocytes, which has clinical significance for aged women undergoing assisted reproduction technology.

Effects of adverse fertility-related factors on mitochondrial DNA in the oocyte: a comprehensive review

The decline of oocyte quality has profound impacts on fertilization, implantation, embryonic development, and the genetic quality of future generations. One factor that is often ignored but is involved in the decline of oocyte quality is mitochondrial DNA (mtDNA) abnormalities. Abnormalities in mtDNA affect the energy production of mitochondria, the dynamic balance of the mitochondrial network, and the pathogenesis of mtDNA diseases in offspring. In this review, we have detailed the characteristics of mtDNA in oocytes and the maternal inheritance of mtDNA. Next, we summarized the mtDNA abnormalities in oocytes derived from aging, diabetes, obesity, and assisted reproductive technology (ART) in an attempt to further elucidate the possible mechanisms underlying the decline in oocyte health. Because multiple infertility factors are often involved when an individual is infertile, a comprehensive understanding of the individual effects of each infertility-related factor on mtDNA is necessary. Herein, we consider the influence of infertility-related factors on the mtDNA of the oocyte as a collective perspective for the first time, providing a supplementary angle and reference for multi-directional improvement strategies of oocyte quality in the future. In addition, we highlight the importance of studying ART-derived mitochondrial abnormalities during every ART procedure.

Growth hormone supplementation ameliorates blastocyst euploidy rates and improves pregnancy outcomes in women undergoing preimplantation genetic testing for aneuploidy cycles

BACKGROUND

Growth hormone (GH) supplementation has been shown to improve oocyte quality and live birth, but few studies have examined whether GH can reduce embryonic aneuploidy. Chromosomal abnormalities in preimplantation embryos have been regarded as the principal cause of implantation failure and miscarriage, and an increased percentage of aneuploid embryos has been observed in patient cohorts with unexplained recurrent pregnancy loss (RPL), recurrent implantation failure (RIF), and advanced maternal age.

METHODS

This prospective cohort study was conducted on women whose previous PGT-A cycle ended up with no transferrable blastocysts, or the aneuploidy rate was above 50% and no live birth was acquired. The participants were divided into GH co-treatment and comparison groups according to whether GH was administered in the subsequent PGT-A cycle. In addition, within the GH co-treatment group, the previous failed cycle constituted the self-control group.

RESULTS

208 women were recruited in the study (GH co-treatment group: 96 women, comparison group: 112 women). Compared to the self-control and comparison groups, the rate of euploid blastocysts was significantly higher in the GH co-treatment group (GH vs self-control: 32.00% vs 9.14%, odds ratio [OR]: 4.765, 95% confidence interval [CI]: 2.420-9.385, P < 0.01; GH vs comparison: 32.00% vs. 21.05%, OR: 1.930, 95% CI: 1.106-3.366, P = 0.021), and their frozen embryo transfers resulted in more pregnancies and live births. In the subgroup analysis, for the <35 and 35-40 years groups, the euploidy rate in the GH co-treatment group was significantly higher than those in the self-control and comparison groups, but in the >40 years group, there was no difference in euploidy rate.

CONCLUSION

Our study presents preliminary evidence that GH supplementation may ameliorate blastocyst aneuploidy and improve pregnancy outcomes in women who have previously experienced pregnancy failures along with high aneuploidy rates, particularly in those younger than 40 years. Therefore, the use of GH in such women should be considered. However, considering the limited sample size and mixed indications for PGT-A, further scientific research on the underlying mechanism as well as clinical trials with larger sample sizes are needed to confirm the effects and optimal protocols.

The Clinical Application of Growth Hormone and Its Biological and Molecular Mechanisms in Assisted Reproduction

Growth hormone (GH) has been used as a co-gonadotrophin in assisted reproduction, particularly in poor ovarian responders. The application of GH has been alleged to activate primordial follicles and improve oocyte quality, embryo quality, and steroidogenesis. However, the effects of GH on the live birth rate among women is controversial. Additionally, although the basic biological mechanisms that lead to the above clinical differences have been investigated, they are not yet well understood. The actions of GH are mediated by GH receptors (GHRs) or insulin-like growth factors (IGFs). GH regulates the vital signal transduction pathways that are involved in primordial follicular activation, steroidogenesis, and oocyte maturation. However, the therapeutic windows and duration of GH administration during assisted reproductive technology require further investigation. The review aimed to clarify the role of GH in human fertility from a molecular and biological point of view to provide evidence for proper GH administration.

Follicular Fluid Growth Factors and Interleukin Profiling as Potential Predictors of IVF Outcomes

Growth hormone (GH) has gained attention as an anti-aging compound enhancing oocyte quality. In fact, GH is known to activate intrafollicular metabolic events for oocyte maturation. Insulin growth factor I (IGF1) is another ovarian growth factor that mediates the FSH and GH actions. Cytokines could also increase IVF outcomes. Indeed, IL-6 is a pleiotropic cytokine with multiple cellular effects that can vary based on the physiological environment. IL-6 may also play an important role in follicular development (Yang et al., J Assist Reprod Genet, 2020, 37 (5), 1171–1176). Clinical studies have been performed to explore the potential role of IL-6 in human oocyte maturation and subsequent embryonic development. To date, the answers are not conclusive. During peri-implantation, many cytokines balances are regulated like pro-inflammatory and anti-inflammatory interleukins. The pro-inflammatory properties of IL-17 and its impact on the tumor microenvironment or autoimmune diseases are characterized, but new dimensions of IL-17 activity that promotes embryo implantation are not well explored. In the search for answers, our study compared concentrations of growth factors IGF1, GH, and interleukins IL-6 and IL-17 in the follicular fluid (FF) from 140 women divided into two groups depending on bad (G1) or good prognosis (G2) and investigated the relationships between these FF components’ levels and the main parameters of IVF. GH, IGF1, and IL-6 were significantly higher for G2. For GH, it was negatively correlated to patient age and positively correlated to maturity rate and IGF1. Moreover, GH and IGF1 were correlated to the top embryo rate and cumulative pregnancy rate. Regarding IL-6, it was correlated to IGF1 level, endometrium thickness, and implantation rate. As for IL-17, it was only correlated to IL-6. Consequently, all these FF components were predictive of oocyte quality except IL-17. GH seemed to be the best biomarker of this quality.

Importance of IGF-I levels in IVF: potential relevance for growth hormone (GH) supplementation

Purpose

Growth hormone (GH) supplementation in association with in vitro fertilization (IVF) is worldwide again increasing, even though study outcomes have been discrepant. Since GH acts via insulin-like growth factor-1 (IGF-1), its utilization in IVF would only seem to make sense with low IGF-1. We, therefore, determined whether IGF-I levels affect IVF outcomes.

Methods

Retrospectively, 302 consecutive first fresh, non-donor IVF cycles were studied, excluding patients on GH supplementation. Patients were divided into 3 subgroups: IGF-1 in lower 25th percentile (group A, < 132 ng/mL, n = 64); 25th–75th percentile (B, 133–202 ng/mL, n = 164), and upper 25th percentile (C, > 202 ng/mL, n = 74). IGF-1 was tested immunochemiluminometric with normal range at 78–270 ng/mL. Because of the study patients’ adverse selection and low pregnancy chances, the main outcome measure for the study was cycle cancellation. Secondary outcomes were oocyte numbers, embryos transferred, pregnancies, and live births.

Results

Group A was significantly older than B and C (P = 0.019). IGF-1 decreased with increasing age per year by 2.2 ± 0.65 ng/mL (P = 0.0007). FSH was best in group B and worst in A (trend, P = 0.085); AMH was best in B and worst in A (N.S.). Cycle cancellations were lowest in C (11.6%) and highest in A (25.0%; P = 0.042). This significance further improved with age adjustment (P = 0.021). Oocytes, embryo numbers, pregnancies, and live birth rates did not differ, though oocyte numbers trended highest in B.

Conclusions

Here presented results support the hypothesis that IGF-1 levels affect IVF outcomes. GH treatments, therefore, may be effective only with low IGF-1.

Regulation of ovarian function by growth hormone: Potential intervention of ovarian aging

Growth hormone (GH) is mainly secreted by eosinophils of anterior pituitary gland. GH plays an important role in regulating the growth and development of many tissues and cells, so it is used in the treatment of many diseases. In recent years, the regulation of GH on ovarian function has attracted much attention. GH has been applied in controlled ovarian hyperstimulation, particularly in the patients with advanced age, diminished ovarian reserve (DOR) and poor ovarian response (POR). GH can directly bind to the growth hormone receptor (GHR) on the ovary to promote the growth, maturation and ovulation of follicles, as well as to inhibit follicular atresia. GH so as to promote the occurrence of early follicles, enhance the sensitivity of follicles to gonadotropins, accelerate the maturation of oocyte nucleus, improve mitochondrial activity and the quality of oocytes through the insulin-like growth factor (IGF) system, which is an indirect regulation. The deep-seated effects of GH on human reproduction and ovarian aging need further basic research and clinical practice.

Recombinant Human Growth Hormone Inhibits Lipotoxicity, Oxidative Stress, and Apoptosis in a Mouse Model of Diabetic Cardiomyopathy

Recombinant human growth hormone (rhGH), widely used in clinical studies, exerts protective effects against cardiac damage. Here, we investigated the effects and mechanisms underlying the effects of rhGH on cardiac functions in db/db mice. C57BL/6J and db/db mice were subjected to rhGH treatment. Metabolic parameters, cardiac function and morphology, oxidative stress, lipid metabolism, and apoptosis were evaluated 16 weeks after rhGH treatment. Although rhGH did not significantly affect fasting blood glucose levels in db/db mice, it protected against diabetic cardiomyopathy, by improving cardiac function and reducing oxidative stress in the heart. In addition, rhGH treatment exhibited anti-apoptotic effects in the heart of db/db mice. The rhGH treatment, besides inhibiting oxidative stress and apoptosis, ameliorated cardiac dysfunction by inhibiting lipotoxicity in mice with type 2 diabetes. These findings suggest that rhGH is a promising therapeutic agent for diabetic cardiomyopathy.

Perfluorooctane sulfonate affects mouse oocyte maturation in vitro by promoting oxidative stress and apoptosis induced bymitochondrial dysfunction

Perfluorooctane sulphonate (PFOS), as a surfactant, is widely applied in the agricultural production activities and has become a potential menace to human health. The mechanism of its effect on the maturation of mammalian oocytes is unclear. This study explored the toxic effect of PFOS on mouse oocyte maturation in vitro. The results revealed that PFOS under a concentration of 600 μM could significantly reduce the polar body extrusion rate (PBE) of mouse oocytes and cause symmetrical cell division. Further experiments showed that PFOS resulted in the abnormal cytoskeleton of the oocytes, causing the abnormal spindles and misplaced chromosomes, as well as the impaired dynamics of actin. Moreover, PFOS exposure inhibited the process of oocyte meiosis, which reflected in the slower spindle migration and continuous activation of spindle assembly checkpoint (SAC), then ultimately increased the probability of aneuploidy. Most importantly, PFOS exposure reduced the quality of oocytes, specifically by disrupting the function of mitochondria, inducing cell oxidative stress, and triggering early apoptosis. Furthermore, the level of methylation of histones is additionally influenced. In summary, our findings showed that PFOS exposure interfered with the maturation of mouse oocytes through affecting cytoskeletal dynamics, meiotic progression, oocyte quality, and histone modifications.

Recent trends in therapeutic strategies for repairing endometrial tissue in intrauterine adhesion

Intrauterine adhesion (IUA) is a common gynaecological disease that develops from infection or trauma. IUA disease may seriously affect the physical and mental health of women of childbearing age, which may lead to symptoms such as hypomenorrhea or infertility. Presently, hysteroscopic transcervical resection of adhesion (TCRA) is the principal therapy for IUAs, although its function in preventing the recurrence of adhesion and preserving fertility is limited. Pharmaceuticals such as hormones and vasoactive agents and the placement of nondegradable stents are the most common postoperative adjuvant therapy methods. However, the repair of injured endometrium is relatively restricted due to the different anatomical structures of the endometrium. Recently, the treatment outcome of IUAs has improved with the advancement of hysteroscopic techniques. In particular, the application of bioactive scaffolds combined with tissue engineering technology has proven to have high therapeutic potential or endometrial repair in IUA treatment. Herein, this review has summarized past therapeutic strategies, including postoperative adjuvant therapy, cell or therapeutic molecular delivery therapy methods and bioactive scaffold-based tissue engineering methods. Therefore, this review presented the recent therapeutic strategies for repairing endometrium treatment and pointed out the issues of clinical concern to provide alternative methods for the management of IUAs.

Nampt affects mitochondrial function in aged oocytes by mediating the downstream effector FoxO3a

Maternal aging can impair the quality and decrease the developmental competence of ovulated oocytes. In this study, compromised germinal vesicle breakdown (GVBD) was found in aged mice oocytes. Furthermore, we observed increased reactive oxygen species (ROS) and mitochondrial Ca²⁺ levels, along with reduced mitochondrial temperature in aged oocytes. Maternal aging also changed the crotonylation level in oocytes. Forkhead box O3 (FoxO3a), a member of the forkhead protein family involved in the regulation of cell survival and life span reached a peak level in the metaphase II stage. Compared with a younger group, FoxO3a expression increased in aged oocytes. Intracellular localization of FoxO3a changed from the cytoplasm to chromatin in response to aging. The expression of the upstream regulator nicotinamide-phosphoribosyltransferase (Nampt) peaked in the GVBD stage. Moreover, Nampt expression was increased in aged oocytes, and more intense staining of Nampt was found in aged mice ovary. To further study the role of Nampt in mitochondrial function, specific agonist P7C3 and inhibitor FK866 were applied to aged oocytes, and FK866 significantly decreased adenosine triphosphate and mitochondrial membrane potential. In conclusion, mitochondrial dysfunction in aged oocytes was associated with elevated FoxO3a, and suppression of Nampt could further impair mitochondrial function.

Research progress of melatonin (MT) in improving ovarian function: a review of the current status

Melatonin (MT) is an endogenous hormone mainly synthesized by pineal cells, which has strong endogenous effects of eliminating free radicals and resisting oxidative damages. Melatonin (MT) can not only regulate the body’s seasonal and circadian rhythms; but also delay ovarian senescence, regulate ovarian biological rhythm, promote follicles formation, and improve oocyte quality and fertilization rate. This review aimd to provide evidence concerning the synthesis and distribution, ovarian function, and role of MT in development of follicles and oocytes. Moreover, the role of MT as antioxidative, participating in biological rhythm regulation, was also reviewed. Furthermore, the effects of MT on various ovarian related diseases were analyzed, particularly for the ovarian aging and polycystic ovary syndrome (PCOS).

Understanding oocyte ageing: can we influence the process as clinicians?

PURPOSE OF REVIEW

Oocyte quality is rate-limiting for pregnancy success and declines with age. Here, I review animal-study evidence showing dramatic reversal of oocyte ageing with mitochondrial nutrients and explore clinical evidence related to their usage.

RECENT FINDINGS

Oocyte ageing is strongly tied to mitochondrial dysfunction and oxidative stress. Quality-defining events occur over a protracted period (2-3 months in humans) when oocyte volume increases over 100-fold. Treating mice during the growth phase with mitochondrial modifiers such as CoQ10 combats oocyte ageing. Exciting new work shows that raising oocyte NAD+ levels also dramatically rejuvenate aged oocytes. However, evidence that any of these agents can reproducibly improve quality in humans is lacking. This is largely because there has been a focus on patients with poor ovarian response during IVF and/or low ovarian follicular pool size, rather than patients with poor oocyte quality. In addition, studies have used short-term treatment during ovarian stimulation after oocyte growth is already complete.

SUMMARY

Mitochondrial therapeutics such as NAD+-boosting used during the oocyte's growth phase markedly improve oocyte quality in mice. Evaluating them in humans should focus on patients with poor oocyte quality and utilise per-oocyte (rather than per-cycle) endpoints after adequate treatment that captures the growth phase when quality is defined.

Study on the Reparative Effect of PEGylated Growth Hormone on Ovarian Parameters and Mitochondrial Function of Oocytes From Rats With Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI) is a heterogeneous disorder and lacks effective interventions in clinical applications. This research aimed to elucidate the potential effects of recombinant human PEGylated growth hormone (rhGH) on follicular development and mitochondrial function in oocytes as well as ovarian parameters in POI rats induced by the chemotherapeutic agent. The impacts of rhGH on ovarian function before superovulation on follicles, estrous cycle, and sex hormones were evaluated. Oocytes were retrieved to determine oocyte quality and oxidative stress parameters. Single-cell sequencing was applied to investigate the latent regulatory network. This study provides new evidence that a high dosage of rhGH increased the number of retrieved oocytes even though it did not completely restore the disturbed estrous cycle and sex hormones. rhGH attenuated the apoptosis of granulosa cells and oxidative stress response caused by reactive oxygen species (ROS) and mitochondrial superoxide. Additionally, rhGH modulated the energy metabolism of oocytes concerning the mitochondrial membrane potential and ATP content but not mtDNA copy numbers. Based on single-cell transcriptomic analysis, we found that rhGH directly or indirectly promoted the balance of oxidative stress and cellular oxidant detoxification. Four hub genes, Pxmp4, Ehbp1, Mt-cyb, and Enpp6, were identified to be closely related to the repair process in oocytes as potential targets for POI treatment.

Supplementation of the In Vitro Maturation Culture Medium of Mouse Oocytes with Growth Hormone Improves Pregnancy Outcomes

This study aimed to examine the effects of adding growth hormone (GH) into the in vitro maturation (IVM) culture medium of mouse oocytes on pregnancy outcomes. Cumulus-oocyte complexes (COCs) were cultured in a medium with (GH group, 100 ng/mL) or without (Con group) GH. Thereafter, chromosome morphology, spindle morphology, and mitochondrial function were examined. Embryo development and blastocyst quality after in vitro fertilization were evaluated. After the embryo transfer, the implantation sites and pregnancy outcomes were evaluated. The oocyte maturation rate of the GH group (81.8 ± 9.6%) was compared to that of the Con group (81.3 ± 6.9%, P = 0.928). The proportion of morphologically abnormal spindles in GH-treated oocytes (7.1 ± 0.9%) was significantly lower than control oocytes (13.7 ± 1.3%, P = 0.032), whereas the proportion of morphologically abnormal chromosomes and mitochondrial distribution was similar between the groups. The mitochondrial membrane potential (P < 0.001) and ATP concentration (P < 0.001) in GH-exposed oocytes were higher than those in control oocytes. After fertilization, the blastocyst rate in the GH group (33.8 ± 13.2%) was significantly higher than the Con group (16.2 ± 2.0%, P = 0.003). In addition, inner cell mass (ICM) number (13.91 ± 3.48 vs. 7.00 ± 1.91, P < 0.001), total cell number (47.45 ± 8.39 vs. 37.71 ± 4.15, P = 0.007), and the ratio of ICM/total cell number (29.9 ± 8.2% vs. 18.6 ± 5.0%, P = 0.002) of blastocyst were all higher in GH group. The implantation rate (71.2 ± 1.9% vs. 39.4 ± 16.4%, P < 0.001) and litter size (8.50 ± 3.99 vs. 3.00 ± 1.22, P = 0.018) were significantly higher in the GH group. Although addition of GH into IVM culture medium does not improve oocyte maturation rate, it improves oocyte and embryo quality, which leads to better embryo development and pregnancy outcomes.

Growth hormone ameliorates the age-associated depletion of ovarian reserve and decline of oocyte quality via inhibiting the activation of Fos and Jun signaling

Oocyte quality typically begins to decline with aging, which contributes to subfertility and infertility. However, there is still no effective treatment to restore the ovarian reserve and improve aged-oocyte quality. According to the present study, growth hormone (GH) secretion changes with maternal age in female mice. After intraperitoneal injection with GH (1 mg/kg body weight) every two days for two months, the 10-month-old mice showed a better ovarian reserve and oocyte quality than control mice. GH treatment decreased the occurrence rate of aneuploidy caused by spindle/chromosome defects. Additionally, the single oocyte transcriptome analysis indicated that GH decreased the expression of apoptosis-related genes in oocytes. It was also observed that GH treatment reduced the expression of γH2AX and apoptosis of aged oocytes via decreasing the activation of Fos and Jun. Collectively, our results indicate that GH treatment is an effective way to reverse the age-associated depletion of ovarian reserve and the decline of oocyte quality by decreasing apoptosis.

Ovarian Rejuvenation Using Autologous Platelet-Rich Plasma

Advanced maternal age is associated with the natural oocyte depletion, leading to low oocyte yield, high infertility treatment cancellation rates, and eventual decreases in pregnancy rates. Various innovative interventions have been introduced to improve the outcome of infertility treatment for aging patients. Numerous published data demonstrated that early follicle development was regulated by intraovarian growth factors through autocrine or paracrine mechanisms. Platelet-rich plasma (PRP), a plasma fraction of peripheral blood with a high concentration of platelets, has been implemented in regenerative medicine in the last decade. The plasma contains a variety of growth factors that were suggested to be able to enhance angiogenesis regeneration and the cell proliferation process. The initial report showed that an intraovarian injection of PRP improved the hormonal profile and increased the number of retrieved oocytes in patients with diminished ovarian reserve. Subsequently, several studies with larger sample sizes have reported that this approach resulted in several healthy live births with no apparent complications. However, the use of ovarian PRP treatment needs to be fully investigated, because no randomized controlled trial has yet been performed to confirm its efficacy.

Electrofusion Stimulation Is an Independent Factor of Chromosome Abnormality in Mice Oocytes Reconstructed via Spindle Transfer

Oocytes reconstructed by spindle transfer (ST) are prone to chromosome abnormality, which is speculated to be caused by mechanical interference or premature activation, the mechanism is controversial. In this study, C57BL/6N oocytes were used as the model, and electrofusion ST was performed under normal conditions, Ca²⁺ free, and at room temperature, respectively. The effect of enucleation and electrofusion stimulation on MPF activity, spindle morphology, γ-tubulin localization and chromosome arrangement was compared. We found that electrofusion stimulation could induce premature chromosome separation and abnormal spindle morphology and assembly by decreasing the MPF activity, leading to premature activation, and thus resulting in chromosome abnormality in oocytes reconstructed via ST. Electrofusion stimulation was an independent factor of chromosome abnormality in oocytes reconstructed via ST, and was not related to enucleation, fusion status, temperature, or Ca²⁺. The electrofusion stimulation number should be minimized, with no more than 2 times being appropriate. As the electrofusion stimulation number increased, several typical abnormalities in chromosome arrangement and spindle assembly occurred. Although blastocyst culture could eliminate embryos with chromosomal abnormalities, it would significantly decrease the number of normal embryos and reduce the availability of embryos. The optimum operating condition for electrofusion ST was the 37°C group without Ca²⁺.

Growth Hormone Cotreatment for Low-Prognosis Patients According to the POSEIDON Criteria

BACKGROUND

Poor ovarian response (POR) remains one of the most challenging conditions in assisted reproduction technology. Previous studies seemed to indicate that growth hormone (GH) was a potential solution for the dilemma of POR; however, the role GH played on the low-prognosis patients diagnosed and stratified by the POSEIDON criteria remains indistinct.

METHODS

This retrospective study was performed among women with POR according to the POSEIDON criteria who failed a previous in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycle, and the subsequent cycle was under GH cotreatment and conducted within 12 months. These participants were stratified into four groups according to the POSEIDON criteria. The comparison was implemented between the failed cycle and the cycle treated with GH. Generalized estimating equation (GEE) multivariate regression was applied for data analysis.

RESULTS

A total of 428 low-prognosis women were included in this study. GH supplementation improved the live birth rates (47.66%, 28.33%, 45.45%, and 24.07%; in groups 1, 2, 3, and 4, respectively) and the clinical pregnancy rates (OR 19.16, 95% CI 7.87-46.63, p < 0.001; OR 7.44, 95% CI 1.65-33.55, p = 0.009; OR 10.19, 95% CI 2.39-43.52, p = 0.002; OR 27.63, 95% CI 4.46-171.11, p < 0.001; in groups 1, 2, 3, and 4, respectively) in all four POSEIDON groups. The number of oocytes retrieved was significantly elevated in the subgroups with normal ovarian reserve (IRR 1.47, 95% CI 1.36-1.59, p < 0.001; IRR 1.31, 95% CI 1.15-1.49, p < 0.001; in groups 1 and 2, respectively). The number of day-3 good-quality embryos was significantly elevated in the subgroups with either normal ovarian reserve or aged young (IRR 2.13, 95% CI 1.78-2.56, p < 0.001; IRR 1.54, 95% CI 1.26-1.89, p < 0.001; IRR 1.47, 95% CI 1.10-1.98, p = 0.010; in groups 1, 2, and 3, respectively).

CONCLUSION

Growth hormone cotreatment could ameliorate the pregnancy outcome for women with POR under the POSEIDON criteria who failed a previous IVF/ICSI cycle. The application of growth hormone for low-prognosis women who experienced a failed cycle might be considered and further studied.

Clinical Application of Antioxidants to Improve Human Oocyte Mitochondrial Function: A Review

Mitochondria produce adenosine triphosphate (ATP) while also generating high amounts of reactive oxygen species (ROS) derived from oxygen metabolism. ROS are small but highly reactive molecules that can be detrimental if unregulated. While normally functioning mitochondria produce molecules that counteract ROS production, an imbalance between the amount of ROS produced in the mitochondria and the capacity of the cell to counteract them leads to oxidative stress and ultimately to mitochondrial dysfunction. This dysfunction impairs cellular functions through reduced ATP output and/or increased oxidative stress. Mitochondrial dysfunction may also lead to poor oocyte quality and embryo development, ultimately affecting pregnancy outcomes. Improving mitochondrial function through antioxidant supplementation may enhance reproductive performance. Recent studies suggest that antioxidants may treat infertility by restoring mitochondrial function and promoting mitochondrial biogenesis. However, further randomized, controlled trials are needed to determine their clinical efficacy. In this review, we discuss the use of resveratrol, coenzyme-Q10, melatonin, folic acid, and several vitamins as antioxidant treatments to improve human oocyte and embryo quality, focusing on the mitochondria as their main hypothetical target. However, this mechanism of action has not yet been demonstrated in the human oocyte, which highlights the need for further studies in this field.

Effects of Growth Hormone Supplementation on Poor Ovarian Responders in Assisted Reproductive Technology: a Systematic Review and Meta-analysis

To investigate whether additional growth hormone (GH) treatment can improve pregnancy outcomes in poor ovarian responders (POR), this systematic review and meta-analysis is prospectively designed and has been registered in PROSPERO (Registration number: CRD42019137866). Literature search was conducted in PubMed, EMBASE, Web of Science, and Cochrane Library from January 2010 to June 2019, and studies before 2010 were included based on a Cochrane review published in 2010. Only English articles and randomized clinical trial studies were included. A total of 12 studies were included for analysis. GH treatment in poor ovarian responders significantly increased the clinical pregnancy rate (odds ratio (OR) = 1.75 (1.23, 2.50)), and the live birth rate also tended to increase after GH treatment (OR = 1.51 (0.97, 2.35)). Other outcomes including the gonadotropin requirement, oocyte retrieval number, endometrium thickness, and the number of patients with available embryos for transfer were also improved by growth hormone treatment (weighted mean differences (WMD) = - 0.78 (- 1.23, - 0.33), 1.41 (0.72, 2.09), 0.36 (0.18, 0.53), OR = 2.67 (1.47, 4.68), respectively). Based on the current study, GH treatment in POR can increase clinical pregnancy rate and show a higher but not statistically significant likelihood of live birth rate. The effect is likely to be mediated by improving ovarian response and endometrium thickness. The effect of GH treatment on live birth rate should be tested by further studies with a larger sample size.

Dynamics and clinical relevance of maternal mRNA clearance during the oocyte-to-embryo transition in humans

Maternal mRNA clearance is an essential process that occurs during maternal-to-zygotic transition (MZT). However, the dynamics, functional importance, and pathological relevance of maternal mRNA decay in human preimplantation embryos have not yet been analyzed. Here we report the zygotic genome activation (ZGA)-dependent and -independent maternal mRNA clearance processes during human MZT and demonstrate that subgroups of human maternal transcripts are sequentially removed by maternal (M)- and zygotic (Z)-decay pathways before and after ZGA. Key factors regulating M-decay and Z-decay pathways in mouse have similar expression pattern during human MZT, suggesting that YAP1-TEAD4 transcription activators, TUT4/7-mediated mRNA 3ʹ-oligouridylation, and BTG4/CCR4-NOT-induced mRNA deadenylation may also be involved in the regulation of human maternal mRNA stability. Decreased expression of these factors and abnormal accumulation of maternal transcripts are observed in the development-arrested embryos of patients who seek assisted reproduction. Defects of M-decay and Z-decay are detected with high incidence in embryos that are arrested at the zygote and 8-cell stages, respectively. In addition, M-decay is not found to be affected by maternal TUBB8 mutations, although these mutations cause meiotic cell division defects and zygotic arrest, which indicates that mRNA decay is regulated independent of meiotic spindle assembly. Considering the correlations between maternal mRNA decay defects and early developmental arrest of in vitro fertilized human embryos, M-decay and Z-decay pathway activities may contribute to the developmental potential of human preimplantation embryos.

How maternal RNA clearance is regulated in human preimplantation embryos is unclear. Here, the authors show there is a potential correlation between maternal mRNA decay defects and early developmental arrest from in vitro fertilized human embryos, suggesting that M-decay and Z-decay pathways may regulate such early development.

Effects of GH/IGF on the Aging Mitochondria

The mitochondria are key organelles regulating vital processes in the eukaryote cell. A decline in mitochondrial function is one of the hallmarks of aging. Growth hormone (GH) and the insulin-like growth factor-1 (IGF-1) are somatotropic hormones that regulate cellular homeostasis and play significant roles in cell differentiation, function, and survival. In mammals, these hormones peak during puberty and decline gradually during adulthood and aging. Here, we review the evidence that GH and IGF-1 regulate mitochondrial mass and function and contribute to specific processes of cellular aging. Specifically, we discuss the contribution of GH and IGF-1 to mitochondrial biogenesis, respiration and ATP production, oxidative stress, senescence, and apoptosis. Particular emphasis was placed on how these pathways intersect during aging.

Does growth hormone supplementation improve oocyte competence and IVF outcomes in patients with poor embryonic development? A randomized controlled trial

BACKGROUND

Many studies have demonstrated the benefits of the addition of growth hormone (GH) to the controlled ovarian stimulation protocol in vitro fertilization (IVF) cycles in poor-respond patients, but the effect of GH on patients with poor embryonic development remain unclear. This paper was designed to investigate the efficacy of GH co-treatment during IVF for the patients with poor embryonic development.

METHOD

A randomized controlled trial including 158 patients with poor embryo development was conducted between July 2017 and February 2019. One hundred and seven patients were randomized for GH treatment (GH group) and 51 patients for untreated (control group). The primary end-points were the clinical pregnancy and live birth rates in the two groups. The oocyte competence were assessed through calculating the mitochondrial DNA (mtDNA) copy number in corresponding cumulus granulosa cells (CGCs). Quantitative PCR were used for calculation of mtDNA copy number.

RESULTS

Relative to the control group, GH co-treatment resulted in a significantly higher number of retrieved oocytes (10.29 ± 5.92 versus 8.16 ± 4.17, P = 0.023) and cleaved embryos (6.73 ± 4.25 versus 5.29 ± 3.23, P = 0.036). The implantation rate, clinical pregnancy rates per cycle, and live birth rate per cycle were higher in the GH group than in the control group (36.00% versus 17.86%, P = 0.005; 43.93% versus 19.61%, P = 0.005; 41.12% versus 17.65%, P = 0.006). CGCs of the GH group had significantly higher mtDNA copy numbers than CGCs of the control group (252 versus 204, P < 0.001).

CONCLUSIONS

These data provided further evidence to indicate that GH supplementation may support more live births during IVF, in patients with poor embryonic development. It also appears that oocytes generated under GH co-treatment have a better developmental competence.

TRIAL REGISTRATION

ChiCTR1900021992 posted March 19, 2019 (retrospectively registered).

The Potential Role of Growth Hormone on the Endometrium in Assisted Reproductive Technology

Growth hormone (GH) has been considered as an adjuvant treatment in human assisted reproductive technology (ART) for several years. Its action was largely attributed to an improvement of ovarian function and less emphasis was paid to its role in the uterus. However, there is increasing evidence that GH and its receptors are expressed and have actions in the endometrium and may play an important role in modifying endometrial receptivity. Thus, in this review, we firstly describe the existence of GH receptors in endometrium and then summarize the effects of GH on the endometrium in clinical situations and the underlying mechanisms of GH in the regulation of endometrial receptivity. Finally, we briefly review the potential risks of GH in ART and consider rationalized use of GH treatment in ART.