Inositols: From Established Knowledge to Novel Approaches

Abstract

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.

Positive Effect of a New Combination of Antioxidants and Natural Hormone Stimulants for the Treatment of Oligoasthenoteratozoospermia

“…Many substances found in nature have such effects [ 5 , 13 ]. In particular, inositol seems to have specific effects on certain hormonal markers, favouring an increase in plasma concentrations of LH, followed by those of testosterone, through stimulation of Leydig cells in the testicles interstitium [ 14 ]. In vitro supplementation of myo-inositol is able to significantly improve sperm motility in a dose-dependent manner [ 15 ], demonstrating a protective role during sperm cryopreservation [ 16 ].…”

Effect of gestational diabetes mellitus on lipid profile: A systematic review and meta-analysis

“…Myo-inositol and d -chiro-inositol are natural compounds involved in many biological pathways and both are currently well tolerated. They are effective alternatives to classical insulin sensitizers and are useful in the prevention and treatment of metabolic and reproductive disorders such as polycystic ovary syndrome and GDM [ 2 , 3 ]. In the last decade, the prevalence of GDM has increased due to inactivity, obesity, and increasing age of mothers.…”

The reliability of biomedical science: A case history of a maturing experimental field

“…One of to their authors' EGOI membership, implying that this might be a sign of academic authority. And, strikingly, a substantial recent review article on inositols that was co-authored by no less than 40 geographically scattered EGOI members [76] stated that every one of them had 'agreed to' all of it. the next challenges is to figure out how these (and other, still undiscovered?)…”