Quantifying the effectiveness and cost-efficiency of food supplementation with antioxidants for male infertility

Effect of Antioxidants on Sperm Quality Parameters in Subfertile Men: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Antioxidant supplementation has been identified as an important intervention for subfertile men. However, the effectiveness of different antioxidants in improving sperm quality remains unclear. In this study, a network meta-analysis (NMA) was designed to evaluate the effects of different antioxidants on sperm quality parameters in subfertile men. Published randomized controlled trials (RCTs) of antioxidants in subfertile men were searched in the PubMed, Embase, and Cochrane Library databases from inception to January 31, 2021. Eight antioxidants (folic acid, zinc, vitamin E, carnitine, selenium, coenzyme q10 [CoQ10], N-acetylcysteine, and vitamin C) and a placebo (control) were included in our study. A Bayesian NMA with random effects was performed for each outcome (sperm concentration, sperm motility, and sperm morphology); the surface under the cumulative ranking curves (SUCRAs) for the effectiveness of each intervention was applied to identify the optimal intervention. Eighteen studies with 1,790 subfertile men were included in the study. CoQ10 elicited a significant increase in sperm concentration (mean difference [MD] = 5.95; 95% confidence interval [CI] 0.05, 10.79) compared with the placebo; it achieved the highest rank in efficacy among all the antioxidants (SUCRA: 79.4%). With regard to sperm motility, carnitine (MD = 12.43; 95% CI 4.07, 20.26) and CoQ10 (MD = 7.33; 95% CI 0.35, 14.17) showed significant beneficial effects compared with the placebo; the efficacy of carnitine was the highest among all the antioxidants (SUCRA: 88.7%). With regard to sperm morphology, the efficacy of vitamin C tended to be the highest (SUCRA: 93.6%), although it did not show significant beneficial effect (MD = 7.73; 95% CI -0.94, 16.33) compared with the placebo. Overall, for subfertile men, CoQ10 and carnitine interventions showed better effectiveness in increasing sperm concentration and sperm motility, respectively.

SIGNIFICANCE

The effectiveness of different antioxidants in improving sperm quality in subfertile men remains unclear. To the best of our knowledge, this is the first study to compare the effectiveness of different antioxidants on sperm quality parameters in subfertile men.

Drug delivery to the testis: current status and potential pathways for the development of novel therapeutics

Nanotechnology has been increasingly utilized for the targeting and delivery of novel therapeutic agents to different tissues and cell types. The current therapeutic options for testicular disorders fall short in many instances due to difficulty traversing the blood-testis barrier, systemic toxicities, and complicated dosing regiments. For testicular tissue, potential targeting can be obtained either via anatomic methods or specific ligands such as luteinizing hormone or follicle-stimulating hormone analogs. Potential novel therapeutic agents include DNA, RNA, cytokines, peptide receptor antagonists, peptide receptor agonists, hormones, and enzymes. Nanotherapeutic treatment of testicular cancer, infertility, testicular torsion, orchalgia, hypogonadism, testicular infections, and cryptorchidism within the framework of potential target cells are an emerging area of research. While there are many potential applications of nanotechnology in drug delivery to the testis, this remains a relatively unexplored field. This review highlights the current status as well as potential future of nanotechnology in the development of novel therapeutics for testicular disorders.

Influence of reactive oxygen species on human sperm functions and fertilizing capacity including therapeutical approaches

BACKGROUND

Reactive oxygen species (ROS) are an array of molecules including oxygen-centered radicals, which are endowed with one or more unpaired electrons and non-radical oxygen derivatives such as hydrogen peroxide, which behave, to a large extent, like a double-edged sword in human sperm biology. This study aimed to overview the current knowledge of ROS in sperm physiology and pathology, as well as related therapies in spermatozoal dysfunction.

METHODS

We performed this study by searching for keywords from PUBMED, including reactive oxygen species, oxidative stress, sperm function, and antioxidant therapy.

RESULTS AND CONCLUSIONS

Low levels of ROS exert critical function in normal sperm physiology, such as fertilizing ability (acrosome reaction, hyperactivation, capacitation, and chemotaxis) and sperm motility; while increased ROS generation and/or decreased antioxidant capacity leads to the imbalance between oxidation and reduction in living systems, which is called sperm oxidative stress. This condition was widely considered to be a significant contributory factor to sperm DNA damage/apoptosis, lipid peroxidation, and reduced motility, which in turn, increased risk of male factor infertility/subfertility and birth defects. Under the current status quo, numerous subsequent studies have concentrated on antioxidant therapy. Although utility of such a therapeutic strategy significantly improved sperm function and motility in a myriad of experimental and clinical reports, the overall effectiveness still remains controversial mainly due to non-standardized assay to measure the level of ROS and sperm DNA damage, various antioxidant supplementation strategies, and inadequate fertilization and pregnancy data after clinical treatment. Therefore, standardized assessment and evaluation of ROS and total antioxidant capacity in semen should be established to keep ROS in a physiological level and prevent over-treatment of antioxidants toward reductive stress, which should be kept in mind, especially in assisted reproductive procedure. Moreover, the significance of large sample size populations, double-blind randomized, placebo-controlled clinical trials of antioxidant therapies is emphasized in this review to achieve optimal ingredients and dosage of antioxidants for patients with reactive oxygen-induced male fertility/subfertility.

Comparing the effectiveness of infertility treatments by numbers needed to treat (NNT)

To compare the clinical efficiency of different modes of treatment of infertile couples and to estimate the possible benefit of nutraceutical food supplementation (NFS), the numbers needed to treat (NNT) was calculated in 4143 infertile couples based on controlled trials in recent literature and personal data. The NNT expresses the number of individuals who need to be treated to obtain one complementary pregnancy. In female infertility, the NNT of mild or moderate endometriosis was 8.4, and in anti-estrogens treatment of anovulation, it was 5.9. In tamoxifen treatment of idiopathic oligozoospermia, NNT was 3.9, and in antioxidant supplementation, it was 7.8. Treatment of varicocele yielded NNT of 6.3 and 6.8 after 1 year in multi- or single-centre trials, respectively, and NFS lowered the NNT after 3 months to 2.6. Adding NFS to the male partner increased the ongoing pregnancy rate by IVF with NNT of 8.3, and adding NFS to both partners reduced the NNT to 4.0. Although these results were obtained in heterogeneous trials and populations, it is suggested that the NNT should be useful for comparing the effectiveness of different modes of treatment of the infertile couple, and that complementary nutraceutical food supplementation may be beneficial.