How to Achieve High-Quality Oocytes? The Key Role of Myo-Inositol and Melatonin

Abstract

Assisted reproductive technologies (ART) have experienced growing interest from infertile patients seeking to become pregnant. The quality of oocytes plays a pivotal role in determining ART outcomes. Although many authors have studied how supplementation therapy may affect this important parameter for both in vivo and in vitro models, data are not yet robust enough to support firm conclusions. Regarding this last point, in this review our objective has been to evaluate the state of the art regarding supplementation with melatonin and myo-inositol in order to improve oocyte quality during ART. On the one hand, the antioxidant effect of melatonin is well known as being useful during ovulation and oocyte incubation, two occasions with a high level of oxidative stress. On the other hand, myo-inositol is important in cellular structure and in cellular signaling pathways. Our analysis suggests that the use of these two molecules may significantly improve the quality of oocytes and the quality of embryos: melatonin seems to raise the fertilization rate, and myo-inositol improves the pregnancy rate, although all published studies do not fully agree with these conclusions. However, previous studies have demonstrated that cotreatment improves these results compared with melatonin alone or myo-inositol alone. We recommend that further studies be performed in order to confirm these positive outcomes in routine ART treatment.

A Double-Blind, Randomized Prospective Study to Evaluate the Efficacy of Previous Therapy With Melatonin, Myo-inositol, Folic Acid, and Selenium in Improving the Results of an Assisted Reproductive Treatment

“…16 Some have advocated that the supply of certain antioxidants does improve outcomes in ART. 17,18 However, several studies have obtained results similar to our study. Although antioxidants involve a significant improvement in embryonic 2 Clinical Medicine Insights: Therapeutics quality, the remaining parameters tested are not statistically superior.…”

“…In addition, inositols have a sensitizing effect on insulin. 18 It is thought that inositol plays a critical role in oocyte maturation and embryonic development. Previous studies have shown that oral supplements with inositol can reduce oxidative stress and improve stimulation protocols and pregnancy outcomes in nonfertile women with poor-quality oocytes.…”

Melatonin: A Mitochondrial Targeting Molecule Involving Mitochondrial Protection and Dynamics

“…Different from the MPTP, UCPs can be actively regulated by many factors based on the status of the mitochondria. Activation of UCPs usually has beneficial effects on mitochondrial functions including balancing the Δψ, accelerating electron transport and finally reducing ROS formation and cellular oxidative damage [168,169]. Melatonin increases the activity of UCPs either by upregulating gene expression or directly acting on these proteins [57,58,60].…”

Comment on “Inositols: from physiology to rational therapy in gynecological clinical practice”

“…Reflecting these elements on the clinical management, we recently showed MI beneficial effects on semen parameters before in vitro fertilization [4] and that both the isoforms of inositol and combined therapy were effective in improving ovarian function and metabolism in patients with PCOS, although MI showed the most marked effect on the metabolic profile, whereas DCI reduced hyperandrogenism better [2]. Although Unfer et al [1] proposed MI:DCI ratio of 40:1 as the most appropriate, we solicit further studies to establish the best therapeutic strategies based on patient's clinical condition, also in combination with other nutraceuticals [5].…”