The D-chiro-inositol paradox in the ovary

Update on the combination of myo-inositol/d-chiro-inositol for the treatment of polycystic ovary syndrome

In this article, we present a narrative review on the use of inositol in the treatment of polycystic ovary syndrome (PCOS). Of the different inositols that exist, only myo-inositol (MYO) and D-chiro inositol (DCI) have been studied in the treatment of PCOS. The results of the studies show that there is insufficient or controversial evidence to recommend the use of DCI alone, while MYO alone shows positive results and, above all, the MYO/DCI combination is effective when used at a ratio of at least 40:1, but there is enough rationale to further study ratios such as 66:1 to 100:1 as other possible effective combinations.

Treatment With a Patented 3.6:1 Myo-Inositol to D-chiro-Inositol Ratio, Antioxidants, Vitamins and Minerals Food Supplement in Women With a History of Assisted Reproductive Technique (ART) Failures: A Series of Case Reports

Infertility affects 15% of couples in reproductive age worldwide. In women in particular, infertility can be caused by various abnormalities, with polycystic ovary syndrome (PCOS) being the most common. Currently, there are many assisted reproductive techniques (ART) available to combat the burden of infertility. However, positive results are not guaranteed. The administration of inositol has been shown to increase positive reproductive outcomes in women undergoing ART. Here we present a series of clinical cases in which women with a history of infertility and previously failed ART, supplemented with a specific 3.6:1 MYO:DCI ratio, antioxidants, vitamins, and minerals for a period of 1 to 3 months before undergoing in vitro fertilization (IVF). In this series of case reports, we provide preliminary evidence that supplementation with a specific 3.6:1 MYO to DCI ratio, as well as antioxidants, vitamins, and minerals may contribute positively to female fertility in women undergoing IVF, with a history of primary or secondary infertility and previously failed ART.

The Effects of Myo-Inositol and D-Chiro-Inositol in a Ratio 40:1 on Hormonal and Metabolic Profile in Women with Polycystic Ovary Syndrome Classified as Phenotype A by the Rotterdam Criteria and EMS-Type 1 by the EGOI Criteria

SETTING

Insulin resistance (IR) and compensatory hyperinsulinemia are considered contributing factors toward polycystic ovary syndrome (PCOS).

OBJECTIVES

This study evaluates the frequency of metabolic abnormalities in PCOS patients and the effects of myo-inositol (MI) and D-chiro-inositol (DCI), in a 40:1 ratio on hormonal and metabolic parameters.

PARTICIPANTS

Thirty-four women with PCOS phenotype A (endocrine-metabolic syndrome [EMS-type 1]) between the ages of 20-40.

DESIGN

Open prospective study with phenotype A (EMS-type I, n = 34) supplemented with 2,255 mg/day of inositol (MI and DCI in a 40:1 ratio) for 3 months.

METHODS

The following were measured before and after treatment: serum levels of follicular stimulating hormone, luteinizing hormone (LH), estradiol, total and free testosterone, sex hormone-binding globulin (SHBG), free androgen index (FAI), anti-Müllerian hormone, glucose, insulin, HOMA-IR, and body mass index (BMI).

RESULTS

55.9% of the enrolled patients were overweight or obese, 50% affected by IR, 17.6% with a history of gestational diabetes mellitus, and 61.8% had familial diabetes mellitus. At the conclusion of the study, BMI (p = 0.0029), HOMA-IR (p < 0.001) significantly decreased, along with decreased numbers of patients with elevated insulin levels. The supplementation resulted in decreased total testosterone (p < 0.001), free testosterone (p < 0.001), FAI (p < 0.001), and LH (p < 0.001); increased SHBG (p < 0.001) and estradiol (p < 0.001).

LIMITATIONS

The present analysis was limited to a 12-week follow-up, which precluded a long-term evaluation of the effects of MI and DCI combination. Also, this period was insufficient to achieve and analyze clinical changes such as restoration of the menstrual cycle, restoration of reproductive function, and clinical manifestations of hyperandrogenism.

CONCLUSIONS

Supplementation improved metabolic and hormonal profile in PCOS phenotype A (EMS-type I) patients. This builds upon previous work that demonstrated that combined inositol treatment may be effective in PCOS. The study presented herein, used a reduced concentration than in prior literature; however, a significant change in hormonal and metabolic parameters was still observed.

Biological Properties of Cyclitols and Their Derivatives

Cyclitols are polyhydroxy cycloalkanes, each containing at least three hydroxyls attached to a different ring carbon atom. The most important cyclitol derivatives are inositols, quercitols, conduritols and pinitols, which form a group of naturally occurring polyhydric alcohols and are widely found in plants. In addition, synthetic production of cyclitols has gained importance in recent years. Cylitols are molecules synthesized in plants as a precaution against salt or water stress. They have important functions in cell functioning as they exhibit important properties such as membrane biogenesis, ion channel physiology, signal transduction, osmoregulation, phosphate storage, cell wall formation and antioxidant activity. The biological activities of these very important molecules, obtained both synthetically and from the extraction of plants, are described in this review.

Stereoselective Voltammetric Biosensor for Myo-Inositol and D-Chiro-Inositol Recognition

This paper describes the development of a simple voltammetric biosensor for the stereoselective discrimination of myo-inositol (myo-Ins) and D-chiro-inositol (D-chiro-Ins) by means of bovine serum albumin (BSA) adsorption onto a multi-walled carbon nanotube (MWCNT) graphite screen-printed electrode (MWCNT-GSPE), previously functionalized by the electropolymerization of methylene blue (MB). After a morphological characterization, the enantioselective biosensor platform was electrochemically characterized after each modification step by differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The results show that the binding affinity between myo-Ins and BSA was higher than that between D-chiro-Ins and BSA, confirming the different interactions exhibited by the novel BSA/MB/MWCNT/GSPE platform towards the two diastereoisomers. The biosensor showed a linear response towards both stereoisomers in the range of 2-100 μM, with LODs of 0.5 and 1 μM for myo-Ins and D-chiro-Ins, respectively. Moreover, a stereoselectivity coefficient α of 1.6 was found, with association constants of 0.90 and 0.79, for the two stereoisomers, respectively. Lastly, the proposed biosensor allowed for the determination of the stereoisomeric composition of myo-/D-chiro-Ins mixtures in commercial pharmaceutical preparations, and thus, it is expected to be successfully applied in the chiral analysis of pharmaceuticals and illicit drugs of forensic interest.

A Markov-model simulation of IVF programs for PCOS patients indicates that coupling myo-Inositol with rFSH is cost-effective for the Italian Health System

Accumulating evidence suggests that oral supplementation with myo-Inositol (myo-Ins) is able to reduce the amount of gonadotropins and days of controlled ovarian hyperstimulation (COS) necessary to achieve adequate oocyte maturation in assisted reproduction technology (ART) protocols, particularly in women affected by polycystic ovary syndrome (PCOS). We used computational calculations based on simulation modellings. We simulated in vitro fertilization (IVF) procedures-with or without intracytoplasmic sperm injection (ICSI)-with 100,000 virtual patients, accounting for all the stages of the entire IVF procedure. A Monte Carlo technique was used to account for data uncertainty and to generate the outcome distribution at each stage. We considered virtual patients with PCOS undergoing IVF cycles to achieve pregnancy. Computational data were retrieved from clinical experience and published data. We investigated three parameters related to ART protocols: cost of single procedure; efficacy to achieve ongoing pregnancy at 12 gestational weeks; overall cost per single pregnancy. The administration of oral myo-Ins during COH protocols, compared to the standard COH with recombinant Follicle Stimulating Hormone (rFSH) only, may be considered a potential strategy to reduce costs of ART for the Italian Health System.

Myo-Inositol and D-Chiro-Inositol as Modulators of Ovary Steroidogenesis: A Narrative Review

Myo-inositol is a natural polyol, the most abundant among the nine possible structural isomers available in living organisms. Inositol confers some distinctive traits that allow for a striking distinction between prokaryotes and eukaryotes, the basic clusters into which organisms are partitioned. Inositol cooperates in numerous biological functions where the polyol participates or by furnishing the fundamental backbone of several related derived metabolites, mostly obtained through the sequential addition of phosphate groups (inositol phosphates, phosphoinositides, and pyrophosphates). Overall myo-inositol and its phosphate metabolites display an entangled network, which is involved in the core of the biochemical processes governing critical transitions inside cells. Noticeably, experimental data have shown that myo-inositol and its most relevant epimer D-chiro-inositol are both necessary to permit a faithful transduction of insulin and of other molecular factors. This improves the complete breakdown of glucose through the citric acid cycle, especially in glucose-greedy tissues, such as the ovary. In particular, while D-chiro-inositol promotes androgen synthesis in the theca layer and down-regulates aromatase and estrogen expression in granulosa cells, myo-inositol strengthens aromatase and FSH receptor expression. Inositol effects on glucose metabolism and steroid hormone synthesis represent an intriguing area of investigation, as recent results have demonstrated that inositol-related metabolites dramatically modulate the expression of several genes. Conversely, treatments including myo-inositol and its isomers have proven to be effective in the management and symptomatic relief of a number of diseases associated with the endocrine function of the ovary, namely polycystic ovarian syndrome.

The Role of Inositols in the Hyperandrogenic Phenotypes of PCOS: A Re-Reading of Larner’s Results

Polycystic ovarian syndrome (PCOS) is the most common endocrinological disorder in women, in which, besides chronic anovulation/oligomenorrhea and ovarian cysts, hyperandrogenism plays a critical role in a large fraction of subjects. Inositol isomers—myo-Inositol and D-Chiro-Inositol—have recently been pharmacologically effective in managing many PCOS symptoms while rescuing ovarian fertility. However, some disappointing clinical results prompted the reconsideration of their specific biological functions. Surprisingly, D-Chiro-Ins stimulates androgen synthesis and decreases the ovarian estrogen pathway; on the contrary, myo-Ins activates FSH response and aromatase activity, finally mitigating ovarian hyperandrogenism. However, when the two isomers are given in association—according to the physiological ratio of 40:1—patients could benefit from myo-Ins enhanced FSH and estrogen responsiveness, while taking advantage of the insulin-sensitizing effects displayed mostly by D-Chiro-Ins. We need not postulate insulin resistance to explain PCOS pathogenesis, given that insulin hypersensitivity is likely a shared feature of PCOS ovaries. Indeed, even in the presence of physiological insulin stimulation, the PCOS ovary synthesizes D-Chiro-Ins four times more than that measured in control theca cells. The increased D-Chiro-Ins within the ovary is detrimental in preserving steroidogenic control, and this failure can easily explain why treatment strategies based upon high D-Chiro-Ins have been recognized as poorly effective. Within this perspective, two factors emerge as major determinants in PCOS: hyperandrogenism and reduced aromatase expression. Therefore, PCOS could no longer be considered a disease only due to increased androgen synthesis without considering the contemporary downregulation of aromatase and FSH receptors. Furthermore, these findings suggest that inositols can be specifically effective only for those PCOS phenotypes featured by hyperandrogenism.

Long-Lasting Therapies with High Doses of D-chiro-inositol: The Downside

Background: Recent studies reported possible concerns following long-lasting treatments with high doses of D-chiro-inositol in women. However, to date, no clinical trial has investigated or validated these concerns. We addressed this issue both retrospectively and with a prospective pilot study. Methods: For the retrospective analysis, we searched our databases for insulin-resistant women who took 1200 mg/day D-chiro-inositol for 6 months. In our prospective study, we enrolled 10 healthy women to supplement with the same therapeutic scheme. We performed statistical analyses through the Wilcoxon Signed-Rank Test. A p-value < 0.05 was considered significant. Results: Twenty women underwent 6 months of 1200 mg/day D-chiro-inositol. The treatment significantly decreased BMI, glycemia, insulinemia, HOMA-IR, serum levels of LH, total testosterone, and DHEAS. Serum estradiol rose and menstrual abnormalities occurred following the treatment. In our prospective study, we observed increases in serum levels of total testosterone and asprosin in healthy women. Conclusions: This is the first clinical evidence demonstrating that long-term treatments with high dosages of D-chiro-inositol can predispose women to hormonal and menstrual abnormalities. Moreover, the accumulation of D-chiro-inositol following such treatment regimen may lead to detrimental effects in non-reproductive tissues, as demonstrated by the increase in asprosin levels.

Non-Hormonal Treatment Options for Regulation of Menstrual Cycle in Adolescents with PCOS

Menstrual irregularities are one of the main clinical symptoms caused by polycystic ovary syndrome (PCOS). Pharmacological treatment options for non-fertility indications to restore menstrual frequency play an important role in the management of PCOS. Oral contraceptive pills are commonly prescribed for adolescents with menstrual irregularities, however, when contraindicated or poorly tolerated, further pharmacological therapy is required. This systematic literature research aims to provide an overview concerning the effects of non-hormonal pharmacological treatment options on menstrual irregularities in adolescents suffering from PCOS. A systematic literature search in PubMed, Cochrane, Embase, Bio-SISS and Web of Science was performed, including literature from January 1998 to September 2022, using specific keywords in order to find related studies. n = 265 studies were identified of which n = 164 were eligible for further evaluation. Only four placebo-controlled studies were identified, with diverging inclusion and exclusion criteria. Available data on specific non-hormonal off-label use medication primarily consisted of metformin, Glucagon-like peptide 1 receptor agonists, thiazolidinediones, anti-androgen agents (spironolactone, finasteride, flutamide) and supplements (chromium picolinate, myo-inositol). However, only a few have partly pointed out beneficial effects on improving menstrual frequency in patients diagnosed with PCOS. In summary, metformin in dosages of 1500-2550 g/day, GLP-1-analogues and supplements were effective in regulation of menstrual cycles in adolescents diagnosed with PCOS. Menstrual frequency in adolescents with PCOS is essential to prevent hypoestrogenism with long-term consequences. In this context, MET is the most effective and cost- efficient in overweight adolescent girls, also showing beneficial effects in the regulation of insulin sensitivity, especially if COCs are contraindicated or not well-tolerated. Further studies are needed to evaluate therapies in lean and normal-weight girls with PCOS.

Putative Complementary Compounds to Counteract Insulin-Resistance in PCOS Patients

Polycystic ovary syndrome (PCOS) is the most frequent endocrine-metabolic disorder among women at reproductive age. The diagnosis is based on the presence of at least two out of three criteria of the Rotterdam criteria (2003). In the last decades, the dysmetabolic aspect of insulin resistance and compensatory hyperinsulinemia have been taken into account as the additional key features in the etiopathology of PCOS, and they have been widely studied. Since PCOS is a complex and multifactorial syndrome with different clinical manifestations, it is difficult to find the gold standard treatment. Therefore, a great variety of integrative treatments have been reported to counteract insulin resistance. PCOS patients need a tailored therapeutic strategy, according to the patient’s BMI, the presence or absence of familiar predisposition to diabetes, and the patient’s desire to achieve pregnancy or not. The present review analyzes and discloses the main clinical insight of such complementary substances.

Inositols in the ovaries: activities and potential therapeutic applications

INTRODUCTION

Myo-inositol (MI) and d-chiro-inositol (DCI) play a key role in ovarian physiology, as they are second messengers of insulin and gonadotropins. Ex-vivo and in-vitro experiments demonstrate that both isomers are deeply involved in steroid biosynthesis, and that reduced MI-to-DCI ratios are associated with pathological imbalance of sex hormones.

AREAS COVERED

This expert opinion provides an overview of the physiological distribution of MI and DCI in the ovarian tissues, and a thorough insight of their involvement into ovarian steroidogenesis. Insulin resistance and compensatory hyperinsulinemia dramatically reduce the MI-to-DCI ratio in the ovaries, leading to gynecological disorders characterized by hyperandrogenism, altered menstrual cycle and infertility.

EXPERT OPINION

Available evidence indicates that MI and DCI have very specific physiological roles and, seemingly, physiological MI-to-DCI ratios in the ovaries are crucial to maintain the correct homeostasis of steroids. Inositol treatments should be evaluated on the patients' specific conditions and needs, as long-term supplementation of high doses of DCI may cause detrimental effects on the ovarian functionality. In addition, the effects of inositol therapy on the different PCOS phenotypes should be further investigated in order to better tailor the supplementation.

D-chiro-inositol Induces Ovulation in Non-Polycystic Ovary Syndrome (PCOS), Non-Insulin-Resistant Young Women, Likely by Modulating Aromatase Expression: A Report of 2 Cases

Case series

Patients: Female, 19-year-old • Female, 23-year-old

Final Diagnosis: Anovulation

Symptoms: Oligomenorrhea

Medication: —

Clinical Procedure: —

Specialty: Obstetrics and Gynecology

New Insights into the Activities of D-Chiro-Inositol: A Narrative Review

D-chiro-inositol (DCI) is a natural compound detectable in cell membranes, which is highly conserved as a biological signaling molecule. In mammals, its function is primarily characterized in the intracellular transduction cascade of insulin. In particular, insulin signal promotes the release of pivotal DCI-containing molecules. In fact, impaired release of DCI is a common feature of insulin-resistant tissues, and insulin-sensitizing pharmaceuticals induce higher concentrations of free DCI. Moreover, it also plays important roles in several other processes. DCI is involved in the regulation of steroidogenesis, due to its regulatory effects on steroidogenic enzymes, including 17α-hydroxylase, 3β-hydroxysteroid dehydrogenase, and aromatase. Such regulation of various enzymes indicates a mechanism by which the body regulates different processes via a single molecule, depending on its concentration. DCI also reduces the expression of integrin β3, which is an adhesion molecule involved in embryo implantation and cellular phenomena such as survival, stemness, and invasiveness. In addition, DCI seems to have important anti-inflammatory activities, like its 3-O-methyl-ether, called pinitol. In vitro evidence demonstrates that treatment with both compounds induces a reduction in pro-inflammatory factors—such as Nf-κB—and cytokines—such as TNF-α. DCI then plays important roles in several fundamental processes in physiology. Therefore, research on such molecule is of primary importance.

Inositols: From Established Knowledge to Novel Approaches

Myo-inositol (myo-Ins) and D-chiro-inositol (D-chiro-Ins) are natural compounds involved in many biological pathways. Since the discovery of their involvement in endocrine signal transduction, myo-Ins and D-chiro-Ins supplementation has contributed to clinical approaches in ameliorating many gynecological and endocrinological diseases. Currently both myo-Ins and D-chiro-Ins are well-tolerated, effective alternative candidates to the classical insulin sensitizers, and are useful treatments in preventing and treating metabolic and reproductive disorders such as polycystic ovary syndrome (PCOS), gestational diabetes mellitus (GDM), and male fertility disturbances, like sperm abnormalities. Moreover, besides metabolic activity, myo-Ins and D-chiro-Ins deeply influence steroidogenesis, regulating the pools of androgens and estrogens, likely in opposite ways. Given the complexity of inositol-related mechanisms of action, many of their beneficial effects are still under scrutiny. Therefore, continuing research aims to discover new emerging roles and mechanisms that can allow clinicians to tailor inositol therapy and to use it in other medical areas, hitherto unexplored. The present paper outlines the established evidence on inositols and updates on recent research, namely concerning D-chiro-Ins involvement into steroidogenesis. In particular, D-chiro-Ins mediates insulin-induced testosterone biosynthesis from ovarian thecal cells and directly affects synthesis of estrogens by modulating the expression of the aromatase enzyme. Ovaries, as well as other organs and tissues, are characterized by a specific ratio of myo-Ins to D-chiro-Ins, which ensures their healthy state and proper functionality. Altered inositol ratios may account for pathological conditions, causing an imbalance in sex hormones. Such situations usually occur in association with medical conditions, such as PCOS, or as a consequence of some pharmacological treatments. Based on the physiological role of inositols and the pathological implications of altered myo-Ins to D-chiro-Ins ratios, inositol therapy may be designed with two different aims: (1) restoring the inositol physiological ratio; (2) altering the ratio in a controlled way to achieve specific effects.

An innovative approach to polycystic ovary syndrome

Myo-inositol and D-chiro-inositol are insulin sensitising agents. In the ovary, myo-inositol acts as second messenger of Follicle Stimulating Hormone (FSH). Both molecules were administered to Polycystic Ovary Syndrome (PCOS) women. The gynaecologist Vittorio Unfer was the first to give specific value to myo-inositol for the treatment of PCOS: this important innovation opened new ways of research to identify efficient therapies based on myo-inositol alone or with low doses of D-chiro-inositol. Significant successes were also gained using myo-inositol in treating male and female infertility. Unfer's researches allowed to identify "the D-Chiro-Inositol Paradox in the Ovary" and the best myo-inositol/D-chiro-inositol ratio (40:1) for the treatment of PCOS. Furthermore, his studies allowed to improve the inositol's efficacy using alpha-lactalbumin. As shown in this review, the main stages of Unfer's scientific career have been closely intertwined with important phases of the recent pharmacological research about the topic.

Inositols Depletion and Resistance: Principal Mechanisms and Therapeutic Strategies

Inositols are natural molecules involved in several biochemical and metabolic functions in different organs and tissues. The term "inositols" refers to five natural stereoisomers, among which myo-Inositol (myo-Ins) is the most abundant one. Several mechanisms contribute to regulate cellular and tissue homeostasis of myo-Ins levels, including its endogenous synthesis and catabolism, transmembrane transport, intestinal adsorption and renal excretion. Alterations in these mechanisms can lead to a reduction of inositols levels, exposing patient to several pathological conditions, such as Polycystic Ovary Syndrome (PCOS), hypothyroidism, hormonal and metabolic imbalances, like weight gain, hyperinsulinemia, dyslipidemia, and metabolic syndrome. Indeed, myo-Ins is involved in different physiological processes as a key player in signal pathways, including reproductive, hormonal, and metabolic modulation. Genetic mutations in genes codifying for proteins of myo-Ins synthesis and transport, competitive processes with structurally similar molecules, and the administration of specific drugs that cause a central depletion of myo-Ins as a therapeutic outcome, can lead to a reduction of inositols levels. A deeper knowledge of the main mechanisms involved in cellular inositols depletion may add new insights for developing tailored therapeutic approaches and shaping the dosages and the route of administration, with the aim to develop efficacious and safe approaches counteracting inositols depletion-induced pathological events.

Impact of myo-inositol treatment in women with polycystic ovary syndrome in assisted reproductive technologies

Polycystic ovary syndrome (PCOS) is marked in 30 to 40% by insulin resistance and hyperandrogenism. Myo-inositol (MI) increases insulin sensitivity, decreases hyperandrogenism and improves the menstrual cycle. Its effect during assisted reproductive technologies (ART) has been studied by many authors. We conducted a review of the literature on the impact of MI administration in PCOS women in assisted reproductive technologies. Myo-inositol is effective in normalizing ovarian function, improving oocyte and embryo quality in PCOS, however further evaluations by large multicentre randomized controlled trials are needed to assess the clinical pregnancy and live birth rates in ART.

Pharmacological Approaches to Controlling Cardiometabolic Risk in Women with PCOS

Polycystic ovary syndrome (PCOS) is characterized by elevated androgen production and subclinical changes in cardiovascular and metabolic risk markers. Total cholesterol, high-density lipoprotein (HDL) cholesterol, fasting glucose, and fasting insulin appear to increase specifically in PCOS compared with fertile women. PCOS also confers an increased risk of cardiometabolic disease in later life. Novel biomarkers such as serum’s cholesterol efflux capacity and blood-derived macrophage activation profile may assist in more accurately defining the cardiometabolic risk profile in these women. Aldosterone antagonists, androgen receptor antagonists, 5α-reductase inhibitors, and synthetic progestogens are used to reduce hyperandrogenism. Because increased insulin secretion enhances ovarian androgen production, short-term treatment with metformin and other hypoglycemic agents results in significant weight loss, favorable metabolic changes, and testosterone reduction. The naturally occurring inositols display insulin-sensitizing effects and may be also used in this context because of their safety profile. Combined oral contraceptives represent the drug of choice for correction of androgen-related symptoms. Overall, PCOS management remains focused on specific targets including assessment and treatment of cardiometabolic risk, according to disease phenotypes. While new options are adding to established therapeutic approaches, a sometimes difficult balance between efficacy and safety of available medications has to be found in individual women.

A review of the role of inositols in conditions of insulin dysregulation and in uncomplicated and pathological pregnancy

Inositols, a group of 6-carbon polyols, are highly bioactive molecules derived from diet and endogenous synthesis. Inositols and their derivatives are involved in glucose and lipid metabolism and participate in insulin-signaling, with perturbations in inositol processing being associated with conditions involving insulin resistance, dysglycemia and dyslipidemia such as polycystic ovary syndrome and diabetes. Pregnancy is similarly characterized by substantial and complex changes in glycemic and lipidomic regulation as part of maternal adaptation and is also associated with physiological alterations in inositol processing. Disruptions in maternal adaptation are postulated to have a critical pathophysiological role in pregnancy complications such as gestational diabetes and pre-eclampsia. Inositol supplementation has shown promise as an intervention for the alleviation of symptoms in conditions of insulin resistance and for gestational diabetes prevention. However, the mechanisms behind these affects are not fully understood. In this review, we explore the role of inositols in conditions of insulin dysregulation and in pregnancy, and identify priority areas for research. We particularly examine the role and function of inositols within the maternal-placental-fetal axis in both uncomplicated and pathological pregnancies. We also discuss how inositols may mediate maternal-placental-fetal cross-talk, and regulate fetal growth and development, and suggest that inositols play a vital role in promoting healthy pregnancy.

Inositols in PCOS

(1) Background: Myoinositol (MI) and D-chiro-inositol (DCI) are involved in a number of biochemical pathways within oocytes having a role in oocyte maturation, fertilization, implantation, and post-implantation development. Both inositols have a role in insulin signaling and hormonal synthesis in the ovaries. (2) Methods: Literature search (with key words: inositols, myo-inositol, d-chiro-inositol, PCOS) was done in PubMed until Sept. 2020 and 197 articles were identified, of which 47 were of clinical trials (35 randomized controlled trials). (3) Results: Many studies have demonstrated that in patients with polycystic ovarian syndrome (PCOS) MI treatment improved ovarian function and fertility, decreased the severity of hyperandrogenism including acne and hirsutism, positively affected metabolic aspects, and modulated various hormonal parameters deeply involved in the reproductive axis function and ovulation. Thus treating with MI has become a novel method to ameliorate PCOS symptoms, improve spontaneous ovulation, or induce ovulation. The current review is focused on the effects of MI and DCI alone or in combination with other agents on the pathological features of PCOS with focus on insulin resistance and adverse metabolic outcomes. (4) Conclusions: The available clinical data suggest that MI, DCI, and their combination in physiological ratio 40:1 with or without other compound could be beneficial for improving metabolic, hormonal, and reproductive aspects of PCOS.

Altered Ovarian Inositol Ratios May Account for Pathological Steroidogenesis in PCOS

The presence of abnormal ovarian ratios of myo-inositol (MI) to D-chiro-inositol (DCI) is a recurrent feature in PCOS. Available evidence suggests that MI and DCI may modulate steroid biosynthesis, likely in an opposite manner. Specifically, MI seems to induce estrogen production, while DCI has a role in the synthesis of androgens. Elevated insulin levels, generally associated with PCOS, alter the physiological MI/DCI ratio, increasing MI-to-DCI conversion through activation of a specific epimerase enzyme. DCI directly increases testosterone biosynthesis in thecal cells and reduces its conversion to estradiol by downregulating aromatase enzyme in granulosa cells. This manuscript reviews the literature that supports the connection between altered MI/DCI ratios and pathological steroidogenesis observed in PCOS women. Furthermore, it discusses the application of inositol-based treatment protocols in managing PCOS symptoms and improving the quality of patients' life.

D-Chiro-Inositol Treatment Affects Oocyte and Embryo Quality and Improves Glucose Intolerance in Both Aged Mice and Mouse Models of Polycystic Ovarian Syndrome

Polycystic ovarian syndrome (PCOS) is the main cause of female infertility. It is a multifactorial disorder with varying clinical manifestations including metabolic/endocrine abnormalities, hyperandrogenism, and ovarian cysts, among other conditions. D-Chiro-inositol (DCI) is the main treatment available for PCOS in humans. To address some of the mechanisms of this complex disorder and its treatment, this study examines the effect of DCI on reproduction during the development of different PCOS-associated phenotypes in aged females and two mouse models of PCOS. Aged females (8 months old) were treated or not (control) with DCI for 2 months. PCOS models were generated by treatment with dihydrotestosterone (DHT) on Days 16, 17, and 18 of gestation, or by testosterone propionate (TP) treatment on the first day of life. At two months of age, PCOS mice were treated with DCI for 2 months and their reproductive parameters analyzed. No effects of DCI treatment were produced on body weight or ovary/body weight ratio. However, treatment reduced the number of follicles with an atretic cyst-like appearance and improved embryo development in the PCOS models, and also increased implantation rates in both aged and PCOS mice. DCI modified the expression of genes related to oocyte quality, oxidative stress, and luteal sufficiency in cumulus-oocyte complexes (COCs) obtained from the aged and PCOS models. Further, the phosphorylation of AKT, a main metabolic sensor activated by insulin in the liver, was enhanced only in the DHT group, which was the only PCOS model showing glucose intolerance and AKT dephosphorylation. The effect of DCI in the TP model seemed mediated by its influence on oxidative stress and follicle insufficiency. Our results indicate that DCI works in preclinical models of PCOS and offer insight into its mechanism of action when used to treat this infertility-associated syndrome.

New clinical targets of d-chiro-inositol: rationale and potential applications

INTRODUCTION

Inositols have a key role in ovarian physiology and the literature reports a wealth of studies about the major isomer, myo-inositol (MI). However, information about d-chiro-inositol (DCI) is still scarce, despite the ratio MI:DCI is tissue-specific and actively maintained by an insulin-dependent epimerase enzyme.

AREAS COVERED

This expert opinion provides an overview of the physiological contribution of DCI in regulating steroidogenesis. DCI indeed mediates the intracellular signaling of insulin, which induces the biosynthesis of androgens. Studies on second messengers of insulin also revealed that DCI has a specific role in modulating the activity of aromatase enzyme. Specifically, recent findings demonstrated that DCI influences the enzyme gene expression, thus reducing the conversion of androgens into estrogens.

EXPERT OPINION

Available evidence suggests that the effects of DCI administration may be similar to those of aromatase inhibitors, but without causing hypo-estrogenic states. Therefore, DCI treatments should be evaluated for either estrogen-dependent gynecological conditions or low testosterone states in male subjects.

Inositol Pyrophosphate Pathways and Mechanisms: What Can We Learn from Plants?

The ability of an organism to maintain homeostasis in changing conditions is crucial for growth and survival. Eukaryotes have developed complex signaling pathways to adapt to a readily changing environment, including the inositol phosphate (InsP) signaling pathway. In plants and humans the pyrophosphorylated inositol molecules, inositol pyrophosphates (PP-InsPs), have been implicated in phosphate and energy sensing. PP-InsPs are synthesized from the phosphorylation of InsP6, the most abundant InsP. The plant PP-InsP synthesis pathway is similar but distinct from that of the human, which may reflect differences in how molecules such as Ins(1,4,5)P3 and InsP6 function in plants vs. animals. In addition, PP-InsPs can potentially interact with several major signaling proteins in plants, suggesting PP-InsPs play unique signaling roles via binding to protein partners. In this review, we will compare the biosynthesis and role of PP-InsPs in animals and plants, focusing on three central themes: InsP6 synthesis pathways, synthesis and regulation of the PP-InsPs, and function of a specific protein domain called the Syg1, Pho1, Xpr1 (SPX ) domain in binding PP-InsPs and regulating inorganic phosphate (Pi) sensing. This review will provide novel insights into the biosynthetic pathway and bioactivity of these key signaling molecules in plant and human systems.

Inositols in Polycystic Ovary Syndrome: An Overview on the Advances

This review details the physiologic roles of two insulin sensitizers, myo-inositol (MI) and d-chiro-inositol (DCI). In the human ovary, MI is a second messenger of follicle-stimulating hormone (FSH) and DCI is an aromatase inhibitor. These activities allow a treatment for polycystic ovary syndrome (PCOS) to be defined based on the combined administration of MI and DCI, where the best MI:DCI ratio is 40:1. Moreover, MI enhances the effect of metformin and clomiphene on the fertility of PCOS women seeking pregnancy. As impaired intestinal transport may lead to unsuccessful inositol treatment, we also discuss new data on the use of alpha-lactalbumin to boost inositol absorption. Overall, the physiological activities of MI and DCI dictate the dosages and timing of inositol supplementation in the treatment of PCOS.

Current treatment for polycystic ovary syndrome: focus on adolescence

Polycystic ovary syndrome (PCOS) is the most frequent endocrine disorder in women and it is associated with an increased rate of infertility. Its etiology remains largely unknown, although both genetic and environmental factors play a role. PCOS is characterized by insulin resistance, metabolic disorders and low-grade chronic inflammation. To date, the treatment of PCOS is mainly symptomatic and aimed at reducing clinical signs of hyperandrogenism (hirsutism and acne), at improving menstrual cyclicity and at favoring ovulation. Since PCOS pathophysiology is still largely unknown, the therapeutic interventions currently in place are rarely cause-specific. In such cases, the therapy is mainly directed at improving hormonal and metabolic dysregulations typical of this condition. Diet and exercise represent the main environmental factors influencing PCOS. Thus, therapeutic lifestyle changes represent the first line of intervention, which, in combination with oral contraceptives, represent the customary treatment. Insulin resistance is becoming an increasingly studied target for therapy, most evidence stemming from the time-honored metformin use. Relatively novel strategies also include the use of thiazolidinediones and GLP1-receptor agonists. In recent years, a nutraceutical approach has been added to the therapeutic toolkit targeting insulin resistance. Indeed, emerging data support inositol and alpha-lipoic acid as alternative compounds, alone or in combination with the aforementioned strategies, with favorable effects on ovulation, insulin resistance and inflammation. Nevertheless, additional studies are required in adolescents, in order to assess the effectiveness of diet supplements in preventing negative impacts of PCOS on fertility in adult age. This review focuses on the main therapeutic options for PCOS to date.

Myo-Inositol's Role in Assisted Reproductive Technology: Evidence for Improving the Quality of Oocytes and Embryos in Patients With Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is one of the most common causes of subfertility, and it is characterized by hormonal dysregulation like insulin resistance. Various measures have been taken in the past to overcome this insulin resistance to improve fertility treatment outcomes. The current paper aims to review and compare the existing studies and literature to assess the impact of myo-inositol (MI) on oocyte and embryo quality in assisted reproductive technology (ARTs). We thoroughly searched the PubMed and Google Scholar databases by using the keywords "PCOS, polycystic ovarian syndrome, inositol, oocyte quality, embryo quality, assisted conception, ART, IVF, and in vitro fertilization." Nine articles were finalized for review in this paper. Many of the reviewed studies have shown a trend toward the improvement of embryo quality in women with PCOS after MI supplementation; however, there is a lack of statistically significant evidence to support the use of MI in enhancing the quality of oocyte and/or embryo. Clear evidence regarding the role of MI in enhancing the quality of oocyte and embryo in PCOS is limited. A well-controlled, large, randomized controlled trial is required to definitively accept or refute its role.

Experts' opinion on inositols in treating polycystic ovary syndrome and non-insulin dependent diabetes mellitus: a further help for human reproduction and beyond

Introduction: This Experts' opinion provides an updated scientific support to gynecologists, obstetricians, endocrinologists, nutritionists, neurologists and general practitioners on the use of Inositols in the therapy of Polycystic Ovary Syndrome (PCOS) and non-insulin dependent (type 2) diabetes mellitus (NIDDM).Areas covered: This paper summarizes the physiology of Myo-Inositol (MI) and D-Chiro-Inositol (DCI), two important molecules present in human organisms, and their therapeutic role, also for treating infertility. Some deep differences between the physiological functions of MI and DCI, as well as their safety and intestinal absorption are discussed. Updates include new evidence on the efficacy exerted in PCOS by the 40:1 MI/DCI ratio, and the innovative approach based on alpha-lactalbumin to overcome the decreased therapeutic efficacy of Inositols in some patients.Expert opinion: The evidence suggests that MI, alone or with DCI in the 40:1 ratio, offers a promising treatment for PCOS and NIDDM. However, additional studies need to evaluate some still unresolved issues, such as the best MI/DCI ratio for treating NIDDM, the potential cost-effectiveness of reduced gonadotropins administration in IVF due to MI treatment, or the benefit of MI supplementation in ovulation induction with clomiphene citrate in PCOS patients.

Clinical and Metabolic Effects of Alpha-Lipoic Acid Associated with Two Different Doses of Myo-Inositol in Women with Polycystic Ovary Syndrome

The aim of this retrospective study was to evaluate the effects of a treatment with α-lipoic acid (ALA) associated with two different doses of myo-inositol (MI) on clinical and metabolic features of women with polycystic ovary syndrome (PCOS). Eighty-eight women received the treatment, and 71 among them had complete clinical charts and were considered eligible for this study. All women were treated with 800 mg of ALA per day: 43 patients received 2000 mg of MI and 28 received 1000 mg of MI per day. Menstrual cyclicity, BMI, FSH, LH, estradiol, testosterone, androstenedione, fasting insulin, HOMA-IR, and insulin response to a 2 h OGTT were evaluated before and after 6 months of treatment. The presence of diabetic relatives (DRs) was investigated. Cycle regularity was improved in 71.2% of women. The improvement of menstrual cyclicity occurred regardless of the state of IR and the presence of DRs of the patients. Women with IR mainly showed a significant improvement of metabolic parameters, while those without IR had significant changes of reproductive hormones. Patients with DRs did not show significant changes after the treatment. 85.7% of women taking 2000 mg of MI reported a higher improvement of menstrual regularity than those taking 1000 mg of MI (50%; p < 0.01). In conclusion, ALA + MI positively affects the menstrual regularity of women with PCOS, regardless of their metabolic phenotype, with a more evident effect with a higher dose of MI. This effect seems to be insulin independent. The presence of IR seems to be a predictor of responsivity to the treatment in terms of an improvement of the metabolic profile.

Inositol Treatment for PCOS Should Be Science-Based and Not Arbitrary

The aim of this paper is to critically analyze the composition of many inositol-based products currently used to treat Polycystic Ovary Syndrome (PCOS). Several different combinations of myo-inositol and D-chiro-inositol, with and without additional compounds such as micro- and macroelements, vitamins, and alpha-lipoic acid, have been formulated over the years. Such therapeutic proposals do not take various features of inositol stereoisomers into consideration. As an example, it is important to know that D-chiro-inositol treatment may be beneficial when administered in low doses, yet the progressive increase of its dosage results in the loss of its advantageous effects on the reproductive performance of women and a deterioration in the quality of blastocysts created via in vitro fertilization (IVF). In addition, we have to consider that the intestinal absorption of myo-inositol is reduced by the simultaneous administration of D-chiro-inositol since the two stereoisomers compete with each other for the same transporter that has similar affinity for each of them. A decrease in myo-inositol absorption is also found when it is coadministered with inhibitors of sugar intestinal absorption and/or types of sugars such as sorbitol, maltodextrin, and sucralose. The combination of these may require higher amounts of myo-inositol in order to reach a therapeutic dosage compared to inositol administration alone, a particularly important fact when physicians strive to obtain a specific plasma level of the stereoisomer. Finally, we must point out that D-chiro-inositol was found to be an aromatase inhibitor which increases androgens and may have harmful consequences for women. Therefore, the inositol supplements used in PCOS treatment must be carefully defined. Clinical evidence has demonstrated that the 40 : 1 ratio between myo-inositol and D-chiro-inositol is the optimal combination to restore ovulation in PCOS women. Therefore, it is quite surprising to find that inositol-based treatments for PCOS seem to be randomly chosen and are often combined with useless or even counterproductive molecules, all of which can weaken myo-inositol's efficacy. Such treatments clearly lack therapeutic rationale.

Myo-Inositol and Its Derivatives: Their Emerging Role in the Treatment of Human Diseases

Myo-inositol has been established as an important growth-promoting factor of mammalian cells and animals. The role of myo-inositol as a lipotropic factor has been proven, in addition to its involvement as co-factors of enzymes and as messenger molecules in signal transduction. Myo-inositol deficiency leads to intestinal lipodystrophy in animals and "inositol-less death" in some fungi. Of late, diverse uses of myo-inositol and its derivatives have been discovered in medicinal research. These compounds are used in the treatment of a variety of ailments from diabetes to cancer, and continued research in this direction promises a new future in therapeutics. In different diseases, inositols implement different strategies for therapeutic actions such as tissue specific increase or decrease in inositol products, production of inositol phosphoglycans (IPGs), conversion of myo-inositol (MI) to D-chiro-inositol (DCI), modulation of signal transduction, regulation of reactive oxygen species (ROS) production, etc. Though inositol pharmacology is a relatively lesser-known field, recent years of research has generated a critical mass of information on the subject. This review aims to summarize our current understanding on the role of inositol derivatives in ameliorating the symptoms of different diseases.

Inositol for subfertile women with polycystic ovary syndrome

BACKGROUND

Subfertile women are highly motivated to try different adjunctive therapies to have a baby, and the widespread perception is that dietary supplements such as myo-inositol (MI) and D-chiro-insoitol (DCI) are associated with only benefit, and not with harm. Many fertility clinicians currently prescribe MI for subfertile women with polycystic ovary syndrome (PCOS) as pre-treatment to in vitro fertilisation (IVF) or for ovulation induction; however no high-quality evidence is available to support this practice. This review assessed the evidence for the effectiveness of inositol in subfertile women with a diagnosis of PCOS.

OBJECTIVES

To evaluate the effectiveness and safety of oral supplementation of inositol for reproductive outcomes among subfertile women with PCOS who are trying to conceive.

SEARCH METHODS

We searched the following databases (to July 2018): Cochrane Gynaecology and Fertility Group (CGFG) Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and AMED. We also checked reference lists and searched the clinical trials registries.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared any type, dose, or combination of oral inositol versus placebo, no treatment/standard treatment, or treatment with another antioxidant, or with a fertility agent, or with another type of inositol, among subfertile women with PCOS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected eligible studies, extracted data, and assessed risk of bias. The primary outcomes were live birth and adverse effects; secondary outcomes included clinical pregnancy rates and ovulation rates. We pooled studies using a fixed-effect model, and we calculated odds ratios (ORs) with 95% confidence intervals (CIs). We assessed the overall quality of the evidence by applying GRADE criteria.

MAIN RESULTS

We included 13 trials involving 1472 subfertile women with PCOS who were receiving myo-inositol as pre-treatment to IVF (11 trials), or during ovulation induction (two trials). These studies compared MI versus placebo, no treatment/standard, melatonin, metformin, clomiphene citrate, or DCI. The evidence was of 'low' to 'very low' quality. The main limitations were serious risk of bias due to poor reporting of methods, inconsistency, and lack of reporting of clinically relevant outcomes such as live birth and adverse events.We are uncertain whether MI improves live birth rates when compared to standard treatment among women undergoing IVF (OR 2.42, 95% CI 0.75 to 7.83; P = 0.14; 2 RCTs; 84 women; I² = 0%). Very low-quality evidence suggests that for subfertile women with PCOS undergoing pre-treatment to IVF who have an expected live birth rate of 12%, the rate among women using MI would be between 9% and 51%.We are uncertain whether MI may be associated with a decrease in miscarriage rate when compared to standard treatment (OR 0.40, 95% CI 0.19 to 0.86; P = 0.02; 4 RCTs; 535 women; I² = 66%; very low-quality evidence). This suggests that among subfertile women with PCOS with an expected miscarriage rate of 9% who are undergoing pre-treatment to IVF, the rate among women using MI would be between 2% and 8%; however this meta-analysis is based primarily on one study, which reported an unusually high miscarriage rate in the control group, and this has resulted in very high heterogeneity. When we removed this trial from the sensitivity analysis, we no longer saw the effect, and we noted no conclusive differences between MI and standard treatment.Low-quality evidence suggests that MI may be associated with little or no difference in multiple pregnancy rates when compared with standard treatment (OR 1.04, 95% CI 0.63 to 1.71; P = 0.89; 2 RCTs; 425 women). This suggests that among subfertile women with PCOS who are undergoing pre-treatment to IVF, with an expected multiple pregnancy rate of 18%, the rate among women using inositol would be between 12% and 27%.We are uncertain whether MI may be associated with an increased clinical pregnancy rate when compared to standard treatment (OR 1.27, 95% CI 0.87 to 1.85; P = 0.22; 4 RCTs; 535 women; I² = 0%; very low-quality evidence). This suggests that among subfertile women with PCOS who are undergoing pre-treatment to IVF, with an expected clinical pregnancy rate of 26%, the rate among women using MI would be between 24% and 40%. Ovulation rates were not reported for this comparison.Other comparisons included only one trial in each, so for the comparisons MI versus antioxidant, MI versus an insulin-sensitising agent, MI versus an ovulation induction agent, and MI versus another DCI, meta-analysis was not possible.No pooled evidence was available for women with PCOS undergoing ovulation induction, as only single trials performed comparison of the insulin-sensitising agent and the ovulation induction agent.

AUTHORS' CONCLUSIONS

In light of available evidence of very low quality, we are uncertain whether MI improves live birth rate or clinical pregnancy rate in subfertile women with PCOS undergoing IVF pre-treatment taking MI compared to standard treatment. We are also uncertain whether MI decreases miscarriage rates or multiple pregnancy rates for these same women taking MI compared to standard treatment. No pooled evidence is available for use of MI versus placebo, another antioxidant, insulin-sensitising agents, ovulation induction agents, or another type of inositol for women with PCOS undergoing pre-treatment to IVF. No pooled evidence is available for use of MI in women undergoing ovulation induction.

The Healing-Promoting Properties of Selected Cyclitols-A Review

INTRODUCTION

Myo-inositol and its derivatives cyclitols play an important role in the processes of cell regulation, signal transduction, osmoregulation, and ion channel physiology, and are a component of the cell membrane. Free cyclitols present in food or released during the degradation of galactosyl cyclitols by bacteria (in digestive tract) show some physiological benefits.

AIM

The aim of this paper is to present and analyze the documented data about curative and healing properties of cyclitols.

RESULTS AND DISCUSSION

Cyclitols are well known compounds in the treatment of an accompanied diabetes insulin resistance, and also obesity and polycystic ovarian syndrome. d-chiro-Inositol deficiency exacerbates insulin resistance in the liver, muscles, and fat, while depletion of myo-inositol results in the development of diabetic complications. Cyclitols are successfully applied in treatment of polycystic ovarian syndrome, simultaneous are observed effective reducing of BMI, improving the hormonal profile, and increasing fertility. Moreover, cyclitols have anti-atherogenic, anti-oxidative, anti-inflammatory, and anti-cancer properties.

CONCLUSION

The properties of cyclitols may be a good therapeutic option in the reduction of metabolically induced inflammation. Due to well drugs tolerance and low toxicity of these compounds, cyclitols are recommend for pregnant women and also for children. Another advantage is their widespread presence and easy availability, which encourages their use in medicine.

Inositols in Insulin Signaling and Glucose Metabolism

In the past decades, both the importance of inositol for human health and the complex interaction between glucose and inositol have been the subject of increasing consideration. Glucose has been shown to interfere with cellular transmembrane transport of inositol, inhibiting, among others, its intestinal absorption. Moreover, intracellular glucose is required for de novo biosynthesis of inositol through the inositol-3-phosphate synthase 1 pathway, while a few glucose-related metabolites, like sorbitol, reduce intracellular levels of inositol. Furthermore, inositol, via its major isomers myo-inositol and D-chiro-inositol, and probably some of its phosphate intermediate metabolites and correlated enzymes (like inositol hexakisphosphate kinase) participate in both insulin signaling and glucose metabolism by influencing distinct pathways. Indeed, clinical data support the beneficial effects exerted by inositol by reducing glycaemia levels and hyperinsulinemia and buffering negative effects of sustained insulin stimulation upon the adipose tissue and the endocrine system. Due to these multiple effects, myoIns has become a reliable treatment option, as opposed to hormonal stimulation, for insulin-resistant PCOS patients.

Inositol in Polycystic Ovary Syndrome: Restoring Fertility through a Pathophysiology-Based Approach

Myo-inositol (MI) and D-chiro-inositol (DCI) are insulin second messengers, and MI is involved in follicular gonadotropin pathways which orchestrate ovulation. The tissue-specific MI/DCI ratio is modulated by insulin through aromatase and is altered in insulin resistance (IR), with reduced epimerization of MI to DCI in insulin-sensitive tissues. In ovaries, the MI/DCI ratio is 100:1, but is dramatically reduced by insulin-stimulated epimerase in hyperinsulinemic women with polycystic ovary syndrome (PCOS). Inositols have proved to be effective in PCOS, improving metabolic and hormonal state, and restoring spontaneous ovulation. In assisted reproductive technology, inositol improved ovarian stimulation parameters, although data concerning fertility outcomes are conflicting. Given their functions, inositols are an attractive treatment option for PCOS, although well-designed studies on spontaneous and non-spontaneous fertility are needed.

Polycystic Ovary Syndrome: Implication for Drug Metabolism on Assisted Reproductive Techniques-A Literature Review

Polycystic ovary syndrome (PCOS) affects 6–10% of women and could be considered one of the most common endocrine alterations in women of reproductive age. The syndrome is characterized by several hormonal and metabolic alterations, including insulin resistance and hyperandrogenism, which play a severe detrimental role in the patient’s fertility. We aimed to offer an overview about drug metabolism in the PCOS population. Nevertheless, we did not find any study that directly compared drug metabolism between PCOS and healthy women. We therefore decided to summarize briefly how hormonal and insulin sensitizer drugs act differently in healthy and PCOS women, who show altered steroidogenesis by theca cells and metabolic imbalance, focusing especially on assisted reproductive techniques. To date, data about drug metabolism in the PCOS population appears to be extremely limited. This important gap could have significant implications for therapeutic approaches and future perspectives: the dosage of drugs commonly used for the treatment of PCOS women should be tailored according to each patient’s characteristics; we should implement new clinical trials in order to identify the best pharmacologic strategy for PCOS patients undergoing in vitro fertilization (IVF); it would be advisable to create an international expert panel to investigate the drug metabolism in the PCOS population.

The effect of nutrient supplementation in the management of polycystic ovary syndrome-associated metabolic dysfunctions: A critical review

Polycystic ovary syndrome (PCOS) is complex heterogeneous disorder that has several aspects in terms of pathology such as metabolic, endocrine, reproductive, and psychological. However, the etiology of PCOS remains poorly understood. Several studies suggest that insulin resistance and hyperandrogenism play a central role in the progression of PCOS pathophysiology. Therefore, common treatment strategies of PCOS are based on lifestyle modification, which include exercise, diet, and nutrient supplementation therapy. Recent studies have recommended some nutrients such as vitamins, minerals, and vitamin-like nutrients for the therapy of PCOS because each has at least one functional property in PCOS-induced pathways. Therefore, it is claimed that the cause of PCOS could be vitamin or mineral deficiency. This review aims to provide a critical literature survey on nutritional supplementation for the treatment of PCOS-associated endocrine and metabolic dysfunctions and discuss the role of nutrients in the management of PCOS in view of the clinical trials and experimental studies.

The use of inositol(s) isomers in the management of polycystic ovary syndrome: a comprehensive review

The aim of this review is to present the current data about the role of inositols in the management of polycystic ovary syndrome (PCOS) women and in the prevention and treatment of gestational diabetes mellitus (GDM). We analyzed the available literature with key words PCOS, Myo-inositol, D-chiro-inositol, assisted reproductive technologies and GDM. The most recent literature would suggest that Myo-inositol, D-chiro-inositol and their combination in physiological ratio 40:1 could represent an important therapeutic strategy for the improvement of metabolic, hormonal and reproductive aspects of PCOS. In assisted reproductive technologies, however, myo-inositol and the combined treatment, despite D-chiro-inositol monotherapy, are able to improve clinical outcomes. Myo-inositol monotherapy results more effective in preventing and treating GDM even if a larger cohort of studies is needed to better clarify these results.

Management of women with PCOS using myo-inositol and folic acid. New clinical data and review of the literature

Introduction The use of 2 × 2000 mg myo-inositol +2 × 200 μg folic acid per day is a safe and promising tool in the effective improvement of symptoms and infertility for patients with polycystic ovary syndrome (PCOS). In addition, PCOS is one of the pathological factors involved in the failure of in vitro fertilization (IVF). Typically, PCOS patients suffer of poor quality oocytes. Patients and methods In an open, prospective, non-blinded, non-comparative observational study, 3602 infertile women used myo-inositol and folic acid between 2 and 3 months in a dosage of 2 × 2000 mg myo-inositol +2 × 200 μg folic acid per day. In a subgroup of 32 patients, hormonal values for testosterone, free testosterone and progesterone were analyzed before and after 12 weeks of treatment. The mean time of use was 10.2 weeks. In the second part of this trial it was investigated if the combination of myo-inositol + folic acid was able to improve the oocyte quality, the ratio between follicles and retrieved oocytes, the fertilization rate and the embryo quality in PCOS patients undergoing IVF treatments. Twenty-nine patients with PCOS, underwent IVF protocols for infertility treatment and were randomized prospectively into two groups. Group A (placebo) with 15 patients and group B (4000 mg myo-inositol +400 μg folic acid per day) with 14 patients were evaluated. The patients of group B used 2 months' myo-inositol + folic acid before starting the IVF protocol. For statistically analyses Student's t-test was performed. Results Seventy percent of the women had a restored ovulation, and 545 pregnancies were observed. This means a pregnancy rate of 15.1% of all the myo-inositol and folic acid users. In 19 cases a concomitant medication with clomiphene or dexamethasone was used. One twin pregnancy was documented. Testosterone levels changed from 96.6 ng/mL to 43.3 ng/mL and progesterone from 2.1 ng/mL to 12.3 ng/mL in the mean after 12 weeks of treatment (p < 0.05) Student's t-test. No relevant side effects were present among the patients. The women in the IVF treatment the group A showed a higher number of retrieved oocytes than group B. Nevertheless, the ratio follicle/retrieved oocyte was clearly better in the myo-inositol group (= group B). Out of the 233 oocytes collected in the myo-inositol group, 136 where fertilized whereas only 128 out of 300 oocytes were fertilized in the placebo group. With regards to the oocytes quality, better data were obtained in the myo-inositol group. More metaphase II and I oocytes were retrieved in relation to the total number of oocytes, when compared with the placebo group. Also, more embryos of grade I quality were observed in the myo-inositol group than in the placebo group. The duration of stimulation was 9.7 days (±3.3) in the myo-inositol group and 11.2 (±1.8) days in the placebo group and the number of used follicle-stimulating hormone (FSH) units was lower in the myo-inositol group in comparison to the placebo group: 1850 FSH units (mean) versus 1850 units (mean). Discussion Myo-inositol has proven to be a new treatment option for patients with PCOS and infertility. The achieved pregnancy rates are at least in an equivalent or even superior range than those reported using metformin as an insulin sensitizer. No moderate to severe side effects were observed when myo-inositol was used at a dosage of 4000 mg per day. In addition, our evidence suggests that a myo-inositol therapy in women with PCOS results in better fertilization rates and a clear trend to a better embryo quality. As by the same way the number of retrieved oocytes was smaller in the myo-inositol group, the risk of a hyperstimulation syndrome in these patients can be reduced. Therefore, myo-inositol also represents an improvement in IVF protocols for patients with PCOS.

Myo-inositol effects in women with PCOS: a meta-analysis of randomized controlled trials

Myo-inositol (MI) supplementation in women with polycystic ovary syndrome (PCOS) has been evaluated over the last years. Many hormonal and reproductive impairments associated with this disorder seem relieved by the supplement. The objective of the meta-analysis was to assess the effects of MI alone or combined with d-chiro-inositol (DCI) on the endocrine and metabolic abnormalities of women with PCOS. Literature was retrieved from selected databases, MEDLINE, EMBASE, PubMed and Research Gate (up to November 2016). Only randomized controlled trials (RCTs) investigating the effects of MI alone or combined with DCI were reviewed. Nine RCTs involving 247 cases and 249 controls were included. Significant decreases in fasting insulin (SMD = -1.021 µU/mL, 95% CI: -1.791 to -0.251, P = 0.009) and homeostasis model assessment (HOMA) index (SMD = -0.585, 95% CI: -1.145 to -0.025, P = 0.041) were identified after MI supplementation. The trial sequential analysis of insulin meta-analysis illustrates that the cumulative z-curve crossed the monitoring boundary, providing firm evidence of the intervention effect. A slight trend toward a reduction of testosterone concentration by MI with respect to controls was found (SMD = -0.49, 95% CI: -1.072 to 0.092, P = 0.099), whereas androstenedione levels remained unaffected. Throughout a subgroup's meta-analysis, a significant increase in serum SHBG was observed only in those studies where MI was administered for at least 24 weeks (SMD = 0.425 nmol/L, 95% CI: 0.050-0.801, P = 0.026). These results highlight the beneficial effect of MI in improving the metabolic profile of women with PCOS, concomitantly reducing their hyperandrogenism.

Inositol supplementation in women with polycystic ovary syndrome undergoing intracytoplasmic sperm injection: a systematic review and meta-analysis of randomized controlled trials

Polycystic ovary syndrome (PCOS) is a complex and heterogeneous disease that involves menstrual dysfunction and reproductive difficulty, as well as metabolic problems. The aim of this study was to assess the effectiveness of myo-inositol (MYO) and d-chiro-inositol (DCI) on improving oocyte or embryo quality and pregnancy rates for women with PCOS undergoing intracytoplasmic sperm injection (ICSI). We searched the Web of Knowledge, MEDLINE, EMBASE, Pubmed, Scopus and Cochrane databases for all articles published in any language up to March 2017. The selection criteria were as follows: (population) patients with PCOS; (intervention) treatment with inositol (MYO, DCI, or both, with any dose and any duration) in conjunction with an ovulation-inducing agent versus the ovulation-inducing agent alone; (outcome) oocyte and embryo quality; (study design) randomized controlled trials. Of 76 identified studies, eight RCTs were included for analysis comprising 1019 women with PCOS. MYO supplementation was insufficient to improve oocyte quality (OR 2.2051; 95% CI 0.8260 to 5.8868), embryo quality (OR 1.6231, 95% CI 0.3926 to 6.7097), or pregnancy rate (OR 1.2832, 95% CI 0.8692 to 1.8944). Future studies of appropriate dose, size and duration of DCI are vital to clarify its the role in the management of PCOS.

Polycystic Ovary Syndrome: Insights into the Therapeutic Approach with Inositols

Polycystic ovary syndrome (PCOS) is characterized by hormonal abnormalities that cause menstrual irregularity and reduce ovulation rate and fertility, associated to insulin resistance. Myo-inositol (cis-1,2,3,5-trans-4,6-cyclohexanehexol, MI) and D-chiro-inositol (cis-1,2,4-trans-3,5,6-cyclohexanehexol, DCI) represent promising treatments for PCOS, having shown some therapeutic benefits without substantial side effects. Because the use of inositols for treating PCOS is widespread, a deep understanding of this treatment option is needed, both in terms of potential mechanisms and efficacy. This review summarizes the current knowledge on the biological effects of MI and DCI and the results obtained from relevant intervention studies with inositols in PCOS. Based on the published results, both MI and DCI represent potential valid therapeutic approaches for the treatment of insulin resistance and its associated metabolic and reproductive disorders, such as those occurring in women affected by PCOS. Furthermore, the combination MI/DCI seems also effective and might be even superior to either inositol species alone. However, based on available data, a particular MI:DCI ratio to be administered to PCOS patients cannot be established. Further studies are then necessary to understand the real contents of MI or DCI uptaken by the ovary following oral administration in order to identify optimal doses and/or combination ratios.

Inositol and In Vitro Fertilization with Embryo Transfer

Recently, studies on inositol supplementation during in vitro fertilization program (IVF) have gained particular importance due to the effect of this molecule on reducing insulin resistance improving ovarian function, oocyte quality, and embryo and pregnancy rates and reducing gonadotropin amount during stimulation. Inositol and its isoforms, especially myoinositol (MYO), are often used as prestimulation therapy in infertile patients undergoing IVF cycle. Inositol supplementation started three months before ovarian stimulation, resulting in significant improvements in hormonal responses, reducing the amount of FSH necessary for optimal follicle development and serum levels of 17beta-estradiol measured the day of hCG injection. As shown by growing number of trials, MYO supplementation improves oocyte quality by reducing the number of degenerated and immature oocytes, in this way increasing the quality of embryos produced. Inositol can also improve the quality of sperm parameters in those patients affected by oligoasthenoteratozoospermia.

Combining treatment with myo-inositol and D-chiro-inositol (40:1) is effective in restoring ovary function and metabolic balance in PCOS patients

Polycystic ovary syndrome (PCOS), a relevant cause of infertility, is a heterogeneous, endocrine disorder affecting up to 10-15% of women in reproductive age. Besides hyperandrogenism, insulin resistance (IR) plays a key role in such syndrome. Insulin-sensitizing drugs, such as Metformin, are effective in treating hyper-insulinemic PCOS patients. Recently, inositols - myo-inositol (MI) and D-chiro-inositol (DCI) - have shown to be an efficient and safe alternative in PCOS management, as both inositol isoforms are able to counteract downstream consequences of insulin resistance. Yet, whereas DCI contributes in mediating insulin activity mainly on non-ovarian tissues, MI displays specific effects on ovary, chiefly by modulating glucose metabolism and FSH-signaling. Moreover, MI may also improve ovarian functions by modulating steroid metabolism through non-insulin-dependent pathways. As DCI and MI activity likely involves different biological mechanisms, both inositol isoforms can be synergistically integrated according to a multitargeted design, by combining MI and DCI in a ratio corresponding to their physiological plasma relative amount (40:1). New experimental and clinical evidence with MI plus DCI evidenced the suitability of such integrated approach, and provided promising results. Further studies need to investigate thoroughly the molecular mechanism and confirm such preliminary data.