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Reproductive Biology and Endocrinology... Jan 2023Metformin is the gold standard insulin sensitizer, which is widely used to treat insulin resistance in polycystic ovary syndrome (PCOS). However, metformin may induce... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Metformin is the gold standard insulin sensitizer, which is widely used to treat insulin resistance in polycystic ovary syndrome (PCOS). However, metformin may induce gastrointestinal side effects.
OBJECTIVE
Inositols have long been debated as a potential alternative for metformin in treating PCOS. Therefore, the present systematic review aimed to evaluate the efficacy and safety of inositols in treating PCOS.
METHODS
The present systematic search was performed in CENTRAL, MEDLINE, and Embase from the inception until October 20th, 2021. Eligible randomized controlled trials (RCTs) included women diagnosed with PCOS and compared any inositols with metformin or placebo. Our primary outcome was cycle normalization, whereas secondary outcomes were body mass index (BMI), parameters of carbohydrate metabolism and clinical and laboratory hyperandrogenism. Results are reported as risk ratios or mean differences (MDs) with 95% confidence intervals (CIs).
RESULTS
Twenty-six RCTs were identified, including data of 1691 patients (806 inositol, 311 with placebo, and 509 metformin groups). In patients treated with inositols, the risk (CI: 1.13; 2.85) of having a regular menstrual cycle was found by 1.79 higher than in the case of placebo. Moreover, the inositols showed non-inferiority compared to metformin in this outcome. In the case of BMI (MD = -0.45; CI: -0.89; -0.02), free testosterone (MD = -0,41, CI: -0.69; -0.13), total testosterone (MD = -20.39, CI: -40.12; -0.66), androstenedione (MD = -0.69, CI: -1,16; -0.22), glucose (MD = -3.14; CI: -5.75; -0.54) levels and AUC insulin (MD = -2081.05, CI: -2745.32; -1416.78) inositol treatment induced greater decrease compared to placebo. Inositol increased sex-hormone-binding globulin significantly compared to placebo (MD = 32.06, CI:1.27; 62.85).
CONCLUSION
Inositol is an effective and safe treatment in PCOS. Moreover, inositols showed non-inferiority in most outcomes compared to the gold standard treatment; metformin.
TRIAL REGISTRATION
PROSPERO registration number: CRD42021283275.
Topics: Female; Humans; Polycystic Ovary Syndrome; Inositol; Hypoglycemic Agents; Randomized Controlled Trials as Topic; Metformin; Testosterone; Insulins
PubMed: 36703143
DOI: 10.1186/s12958-023-01055-z -
International Journal of Molecular... Sep 2021Myo-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... (Review)
Review
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.
Topics: Diabetes, Gestational; Female; Humans; Inositol; Molecular Structure; Polycystic Ovary Syndrome; Pregnancy; Signal Transduction; Testosterone; Theca Cells
PubMed: 34638926
DOI: 10.3390/ijms221910575 -
Reproductive Health Aug 2021Multiple oral insulin-sensitizing agents, such as metformin, thiazolidinediones, inositols, and berberine, have been proven safe and efficacious in improving the... (Meta-Analysis)
Meta-Analysis
Comparative efficacy of oral insulin sensitizers metformin, thiazolidinediones, inositol, and berberine in improving endocrine and metabolic profiles in women with PCOS: a network meta-analysis.
BACKGROUND
Multiple oral insulin-sensitizing agents, such as metformin, thiazolidinediones, inositols, and berberine, have been proven safe and efficacious in improving the endocrine, metabolic, and reproductive abnormalities seen in polycystic ovary syndrome (PCOS), providing more options for healthcare providers and patients. These oral insulin sensitizers are more convenient, practical, and economic than agents that need to be injected. A comparison of the clinical effectiveness of the four different classes of oral insulin sensitizers in PCOS has not been explored, leading to clinical uncertainty about the optimal treatment pathway. The present study aims to compare the effects of oral insulin sensitizers on endocrine and metabolic profiles in women with PCOS.
METHODS
We identified randomized controlled trials for PCOS from a variety of databases, published from January 2005 to October 2020. Outcomes included changes in menstrual frequency, improvements in hyperandrogenism and glucolipid metabolism and adverse side effects. A random-effects network meta-analysis was performed.
RESULTS
Twenty-two trials comprising 1079 patients with PCOS were included in this study. Compared with metformin, treatment with myo-inositol + D-chiro-inositol was associated with a greater improvement in menstrual frequency (odds ratio 14.70 [95% confidence interval (CI) 2.31-93.58]). Myo-inositol + D-chiro-inositol and metformin + thiazolidinediones combination therapies were superior to respective monotherapies in reducing total testosterone levels. Thiazolidinediones, metformin + thiazolidinediones, and myo-inositol + D-chiro-inositol were associated with a lower insulin resistance index (HOMA-IR) compared with that in metformin alone (mean differences: - 0.72 [95% CI (- 1.11)-(- 0.34)] to - 0.89 [95% CI (- 1.460)-(- 0.32)]). Metformin + thiazolidinediones treatment was associated with lower triglyceride levels compared with that in metformin and thiazolidinediones monotherapy, while thiazolidinediones was superior to metformin in increasing high-density lipoprotein cholesterol and decreasing fasting plasma glucose, triglycerides, low-density lipoprotein cholesterol, and gastrointestinal adverse events.
CONCLUSIONS
Ours is the first study to report that for women with PCOS, myo-inositol combined with D-chiro-inositol and metformin combined with thiazolidinediones appear superior to metformin alone in improving insulin resistance and decreasing total testosterone. Myo-inositol combined with D-chiro-inositol is particularly efficacious in menstrual recovery. Thiazolidinediones and metformin combined with thiazolidinediones improve lipid metabolism better than metformin alone. Trial registration PROSPERO CRD42020211524.
Topics: Berberine; Clinical Decision-Making; Female; Humans; Hypoglycemic Agents; Inositol; Insulin; Insulin Resistance; Metabolome; Metformin; Network Meta-Analysis; Polycystic Ovary Syndrome; Thiazolidinediones; Uncertainty
PubMed: 34407851
DOI: 10.1186/s12978-021-01207-7 -
Reproductive Biomedicine Online Dec 2016Studies over the last decade have demonstrated that some polycystic ovary syndrome (PCOS) patients have abnormal insulin sensitivity (insulin resistance), independently... (Review)
Review
Studies over the last decade have demonstrated that some polycystic ovary syndrome (PCOS) patients have abnormal insulin sensitivity (insulin resistance), independently from being overweight or obese. This induces the risk of developing type 2 diabetes in such PCOS patients. The use of insulin sensitizers (i.e. metformin), reduces such metabolic, and most hormonal, impairments. As metformin often induces side effects, new integrative strategies have been proposed to treat insulin resistance, such as the use of inositols. Such compounds are mainly represented in humans by two inositol stereoisomers: myo-inositol (MYO) and d-chiro-inositol (DCI). MYO is the precursor of inositol triphosphate, a second messenger that regulates thyroid-stimulating hormone (TSH) and FSH as well as insulin. DCI derives from the conversion of myo-inositol via an insulin-dependent pathway. Several preliminary studies have indicated possible benefits of inositol therapy in PCOS patients, but to date no meta-analysis has been performed. This review aims to give clinical insights for the clinical use of inositol in PCOS.
Topics: Female; Humans; Hyperandrogenism; Hyperinsulinism; Inositol; Inositol Phosphates; Insulin; Insulin Resistance; Obesity; Overweight; Polycystic Ovary Syndrome; Signal Transduction; Thyrotropin
PubMed: 27717596
DOI: 10.1016/j.rbmo.2016.08.024 -
Molecules (Basel, Switzerland) Nov 2020(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,... (Review)
Review
(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.
Topics: Animals; Female; Humans; Inositol; Ovulation; Polycystic Ovary Syndrome
PubMed: 33260918
DOI: 10.3390/molecules25235566 -
Molecules (Basel, Switzerland) Nov 2020Recently, inositols, especially -inositol and inositol hexakisphosphate, also known as phytic acid or IP6, with their biological activities received much attention for... (Review)
Review
Recently, inositols, especially -inositol and inositol hexakisphosphate, also known as phytic acid or IP6, with their biological activities received much attention for their role in multiple health beneficial effects. Although their roles in cancer treatment and prevention have been extensively reported, interestingly, they may also have distinctive properties in energy metabolism and metabolic disorders. We review inositols and inositol phosphate metabolism in mammalian cells to establish their biological activities and highlight their potential roles in energy metabolism. These molecules are known to decrease insulin resistance, increase insulin sensitivity, and have diverse properties with importance from cell signaling to metabolism. Evidence showed that inositol phosphates might enhance the browning of white adipocytes and directly improve insulin sensitivity through adipocytes. In addition, inositol pyrophosphates containing high-energy phosphate bonds are considered in increasing cellular energetics. Despite all recent advances, many aspects of the bioactivity of inositol phosphates are still not clear, especially their effects on insulin resistance and alteration of metabolism, so more research is needed.
Topics: Adipocytes, White; Animals; Energy Metabolism; Humans; Inositol Phosphates; Insulin Resistance; Signal Transduction
PubMed: 33139672
DOI: 10.3390/molecules25215079 -
European Review For Medical and... Mar 2021Inositol is a carbocyclic sugar polyalcohol. By epimerization of its hydroxyl groups, nine possible stereoisomers can be generated, two of major physiological and... (Review)
Review
OBJECTIVE
Inositol is a carbocyclic sugar polyalcohol. By epimerization of its hydroxyl groups, nine possible stereoisomers can be generated, two of major physiological and clinical relevance: myo-inositol and D-chiro-inositol. Myo-inositol and D-chiro-inositol are normally stored in kidney, brain and liver and are necessary for functions, such as signal transduction, metabolic flux, insulin signaling, regulation of ion-channel permeability, stress response and embryo development. In this narrative review, we summarize the mechanisms by which myo-inositol and D-chiro-inositol can be synthesized and absorbed and their possible role in the etiopathogenesis of neural tube defects.
MATERIALS AND METHODS
We performed an online search in the PubMed database using the following keywords: "inositol", "D-chiro-inositol", "myo-inositol", "neural tube defects and inositol".
RESULTS
Inositol requirements are partly met by dietary intake, while the rest is synthesized endogenously. Inositol deficiency may be involved in the pathogenesis of diseases, such as metabolic syndrome, spina bifida (a neural tube defect), polycystic ovary syndrome and diabetes. Supplementation of the two inositol stereoisomers, D-chiro-inositol and myo-inositol is important to prevent these conditions.
CONCLUSIONS
Inositol is fundamental for signal transduction in the brain, kidneys, reproductive organs and other tissues in response to neurotransmitters, hormones and growth factors. Various genes are involved in inositol metabolism and associated pathways. Altered inositol concentrations are observed in several diseases. Analysis of the genes involved in inositol metabolism may provide important information for the clinical management of these conditions.
Topics: Animals; Humans; Inositol; Molecular Conformation
PubMed: 33755975
DOI: 10.26355/eurrev_202103_25279 -
Nutrients Apr 2023Myo-inositol is a natural polyol, the most abundant among the nine possible structural isomers available in living organisms. Inositol confers some distinctive traits... (Review)
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.
Topics: Humans; Female; Inositol; Aromatase; Polycystic Ovary Syndrome; Inositol Phosphates; Glucose
PubMed: 37111094
DOI: 10.3390/nu15081875 -
European Review For Medical and... Jan 2021D-chiro-Inositol has been widely used in clinical practice to induce ovulation in women with polycystic ovary syndrome. Only recent evidence established that this... (Review)
Review
OBJECTIVE
D-chiro-Inositol has been widely used in clinical practice to induce ovulation in women with polycystic ovary syndrome. Only recent evidence established that this molecule acts through two different mechanisms, with potentially different outcomes. On the one hand, under a metabolic perspective, D-chiro-Inositol improves insulin signaling, thus restoring physiological insulin levels in resistant subjects. On the other hand, at a cellular level, it downregulates the expression of steroidogenic enzyme aromatase, which is responsible for the conversion of androgens to estrogens.
MATERIALS AND METHODS
We reviewed current literature in different databases, searching for D-chiro-Inositol in relation with one of the following keywords: myo-inositol, PCOS, infertility, insulin resistance, aromatase, androgen and inositol, testosterone, estrogen and inositol, estradiol, hypogonadotropic hypogonadism, fat tissue, estrogens and cancer, anovulation, uterine myoma, endometriosis, endometrial hyperplasia.
RESULTS
D-Chiro-Inositol treatment may be helpful in restoring physiological hormonal levels in various clinical disorders. However, D-Chiro-Inositol intervention should be carefully designed to avoid possible undesired side effects stemming from its multiple mechanisms of action.
CONCLUSIONS
We evaluated the optimal D Chiro-Inositol administration for different pathologies, defining dosages and timing. Even though further studies are required to validate our preliminary results, this paper is primarily intended to guide researchers through some of the pathways of D-Chiro-Inositol.
Topics: Aromatase; Down-Regulation; Female; Humans; Inositol; Insulin; Insulin Resistance; Male; Polycystic Ovary Syndrome
PubMed: 33506934
DOI: 10.26355/eurrev_202101_24412 -
Frontiers in Endocrinology 2021Myo-Inositol (MYO) is the most abundant stereoisomer of inositols' family, cyclic polyols with 6 hydroxyl groups. Myo-Inositol has a relevant role in thyroid function... (Review)
Review
Myo-Inositol (MYO) is the most abundant stereoisomer of inositols' family, cyclic polyols with 6 hydroxyl groups. Myo-Inositol has a relevant role in thyroid function and autoimmune diseases, as a precursor of phosphoinositides that takes part in the phosphatidylinositol (PI) signal transduction pathway. Among phosphoinositides, phosphatidylinositol 4,5- bisphosphate (PIP2) is the precursor of inositol triphosphates (IP3), second messenger of several hormones including thyroid-stimulating hormone (TSH). As a second messenger in the phospholipase C (PLC)-dependent inositol phosphate Ca/DAG pathway, Myo-Inositol is essential to produce HO required for the synthesis of thyroid hormones. Consequently, depletion of Myo-Inositol or impaired inositol dependent TSH signaling pathway may predispose to the development of some thyroid diseases, such as hypothyroidism. Many clinical studies have shown that after treatment with Myo-Inositol plus Selenium (MYO+Se), TSH levels significantly decreased in patients with subclinical hypothyroidism with or without autoimmune thyroiditis. The TSH reduction was accompanied by a decline of antithyroid autoantibodies. Moreover, Myo-Inositol supplementation seemed to be involved also in the management of thyroidal benign nodules, with a possible effect in the size reduction. This review proposes a summary of the role of inositol, especially of Myo-Inositol, in the thyroidal physiology and its contribution on the management of some thyroid diseases.
Topics: Humans; Hypothyroidism; Inositol; Thyroid Function Tests; Thyroid Gland; Thyroid Hormones; Vitamin B Complex
PubMed: 34040582
DOI: 10.3389/fendo.2021.662582