Myo‐inositol in health and disease: its impact on semen parameters and male fertility

Abstract

Background Myo‐inositol (cis‐1,2,3,5‐trans‐4,6‐cyclohexanehexol; MI) is the most prominent of nine inositol stereoisomers. MI, its phosphate derivatives, and associated lipids are widely found in vegetables and animal tissues and are known to participate in numerous biological processes. Objectives To perform a review analysis on MI presence, functions, and impact in male fertility. Materials and Methods A thorough search of listed publications in PubMed on MI and its derivatives was done. Results Published information was found and compiled on MI identification, natural dietary sources and absorption, biosynthesis, concentrations, as well as MI as its derivatives (PI, PIP, GPI, IPG) roles in several human tissues and body fluids in health and disease. A section was focused on MI presence, biosynthesis, and functions in the mammalian male genital tract and in spermatozoa, and summarized reports describing the impact of in vivo and in vitro MI supplementation on human semen quality and fertility. Studies reported a discrete improvement in sperm motility in fresh and frozen‐thawed semen, and a better sperm performance in natural and assisted fertility. Discussion and Conclusion MI was reported as an effective supplement for sperm quality. In any case, several study designs lack appropriate controls or data analysis to confirm the relevance of the findings. While promising, larger prospective randomized controlled studies will be required to confirm the positive effect of MI supplementation in male infertility management. Moreover, further investigations are encouraged to unravel MI roles in sperm physiology and the underlying molecular mechanisms.

Oxidative Stress and Male Fertility: Role of Antioxidants and Inositols

“…In recent years, the SLC5A3 cellular transporter was found to be expressed in several tissues. Among others, testis and epididymis displayed (high/medium/low) expression, while Sertoli cells display elevated expression, as the hypertonic conditions increase MI uptake [119,120]. Therefore, here the concentration of MI is 28 times higher compared to the plasma.…”

“…The absorption of free inositol in the intestine is achieved with an active transporter of sodium/myo-inositol transporter (SMIT) family, temperature and pH dependent. SMIT is an active symporter which allows uptake and accumulation, dependently on both concentration of substrates and energy [119,120]. Furthermore, intestinal absorption of a high amount of myo-inositol is considered safe, as highlighted by several studies that proved the absence of side effects even after ingesting large quantities [118].…”

Respiratory Mitochondrial Efficiency and DNA Oxidation in Human Sperm after In Vitro Myo-Inositol Treatment

“…Between others, inositols are cyclic carbohydrates existing in nine stereoisomeric forms: myo-inositol is the most abundant form in nature. Several studies have shown that myo-inositol has powerful antioxidant properties that improve sperm quality, particularly in patients with oligoasthenozoospermia [ 28 , 29 , 30 , 31 ].…”

Relationships between Seminal Plasma Metabolites, Semen Characteristics and Sperm Kinetics in Donkey (Equus asinus)

“…GPC is produced by epididymal cells and released in the epididymal lumen; spermatozoa increase their GPC levels at maturation (for review see [45]). Myo-inositol is a carbocyclic sugar involved in cell signal transduction, antioxidant defenses, and osmoregulation; as phosphatidylinositol or as mono or polyphosphates works as a second messenger in many intracellular signal transduction pathways [46]. It is associated with an improved mitochondrial morphology [47] and membrane potential [48].…”