Dietary supplements in the management of varicocele-induced infertility: A review of potential mechanisms

Varicocele, Functional Foods and Nutraceuticals: From Mechanisms of Action in Animal Models to Therapeutic Application

Varicocele is one of the main causes of infertility in men, thus representing an important clinical problem worldwide. Inflammation contributes mainly to its pathogenesis, even if the exact pathophysiological mechanisms that correlate varicocele and infertility are still unknown. In addition, oxidative stress, apoptosis, hypoxia, and scrotal hyperthermia seem to play important roles. So far, the treatment of varicocele and the care of the fertility-associated problems still represent an area of interest for researchers, although many advances have occurred over the past few years. Recent experimental animal studies, as well as the current epidemiological evidence in humans, demonstrated that many functional foods of natural origin and nutraceuticals that are particularly abundant in the Mediterranean diet showed anti-inflammatory effects in varicocele. The aim of the present narrative review is to mainly evaluate recent experimental animal studies regarding the molecular mechanisms of varicocele and the state of the art about possible therapeutic approaches. As the current literature demonstrates convincing associations between diet, food components and fertility, the rational intake of nutraceuticals, which are particularly abundant in foods typical of plant-based eating patterns, may be a reliable therapeutic supportive care against varicocele and, consequently, could be very useful in the cure of fertility-associated problems in patients.

Mailuoshutong pill for varicocele-associated male infertility—Phytochemical characterisation and multitarget mechanism

Background: Varicocele (VC) is a relatively common and treatable cause of male infertility. Mailuoshutong pill (MLST), a traditional Chinese patent medicine, is widely used for treating varicose vein disease, but the underlying mechanism of MLST on varicocele-associated male infertility is unclear.

Objective: To reveal the phytochemical characterisation and multitarget mechanism of MLST on varicocele-associated male infertility.

Methods: The components in MLST were determined using UHPLC-MS/MS. Through network analysis, we constructed the “Drug-Components-Targets-Disease” network and predicted the potential biological functions and signaling pathways of MLST. Finally, the therapeutic effects and potential mechanisms of MLST were discovered by pharmacological experiments.

Results: By network analysis, the “Drug-Components-Targets-Disease” network was constructed, 62 components such as apigenin, limonin, kaempferol, and obacunoic acid may be the main active components of MLST for varicocele-associated male infertility, 28 targets such as VEGFA, PIK3CA, AKT1, and MTOR are considered as hub targets, signaling pathways such as HIF-1, Estrogen, PI3K/Akt, and mTOR may be key pathways for MLST against varicocele-associated male infertility. Through pharmacological experiments, we found that MLST ameliorated VC-induced testicular atrophy. Further histomorphology showed that MLST reduced VC-induced damage to testicular spermatogonia and seminiferous tubule, while MLST reduced ROS and MDA levels and increased antioxidant enzymes (GSH, GSH-Px, SOD, and CAT) levels. TUNEL staining and immunofluorescence showed that MLST reduced VC-induced apoptosis in testicular tissue, decreased BAX, and increased BCL2. Western blot results showed that MLST decreased the phosphorylation of PI3K, AKT, and mTOR proteins, and decreased the expression of HIF1α.

Conclusion: The phytochemical characterisation and multitarget mechanism of MLST on varicocele-associated male infertility were discovered using network analysis and pharmacological experiments. We verified that MLST can inhibit the activation of the PI3K/Akt/mTOR signaling pathway, reduce the expression of HIF1α, and further attenuate VC-induced oxidative stress and apoptosis in the testis. These findings provide evidence for the therapeutic role of MLST in varicocele-associated male infertility.

Fatty Acid Oxidation and Pro-Resolving Lipid Mediators Are Related to Male Infertility

Specialized pro-resolving lipid mediators regulate the resolution of acute inflammation. They are formed by enzymatic oxygenation of polyunsaturated fatty acids and are divided into families including lipoxins, resolvins, protectins, and maresins. Resolvin D1 (RvD1), produced by docosahexaenoic acid, exerts anti-inflammatory and pro-resolving activities. This research aimed to investigate the implication of seminal RvD1 in human infertility. Infertile patients (n° 67) were grouped based on pathological reproductive conditions as idiopathic infertility, varicocele, and leukocytospermia; the fourth group was composed of fertile men (n° 18). Sperm characteristics were evaluated by light microscopy (WHO guidelines) and by transmission electron microscopy (TEM). The seminal levels of RvD1 and F2-isoprostane (F2-IsoPs) were dosed. In twenty men (6 fertile men, 8 with varicocele, 6 with leukocytospermia) seminal phospholipase A2, iron, cholesterol, transferrin, estradiol, ferritin, testosterone, and sperm membrane fatty acids were detected. The results indicated that: (i) RvD1 amount was positively correlated with F2-IsoPs and reduced sperm quality; (ii) RvD1 levels were significantly higher in patients with leukocytospermia, varicocele, and idiopathic infertility compared to fertile men; (iii) RvD1 increased along with other markers of oxidative stress and inflammation as fatty acids content and clinical biomarkers. This study suggests a panel of inflammatory markers and lipid mediators for a diagnosis of inflammatory status and a subsequent appropriate therapeutic approach.