Improving Sperm Oxidative Stress and Embryo Quality in Advanced Paternal Age Using Idebenone In Vitro—A Proof-of-Concept Study

Abstract

Advanced paternal age is associated with increased sperm reactive oxygen species (ROS) and decreased fertilization and pregnancy rates. Sperm washing during infertility treatment provides an opportunity to reduce high sperm ROS concentrations associated with advanced paternal age through the addition of idebenone. Sperm from men aged >40 years and older CBAF1 mice (12–18 months), were treated with 5 µM and 50 µM of idebenone and intracellular and superoxide ROS concentrations assessed. Following in vitro fertilization (IVF), embryo development, blastocyst differentiation, DNA damage and cryosurvival, pregnancy and implantation rates and fetal and placental weights were assessed. Five µM of idebenone given to aged human and mouse sperm reduced superoxide concentrations ~20% (p < 0.05), while both 5 and 50 µM reduced sperm intracellular ROS concentrations in mice ~30% (p < 0.05). Following IVF, 5 µM of idebenone to aged sperm increased fertilization rates (65% vs. 60%, p < 0.05), blastocyst total, trophectoderm and inner cell mass cell numbers (73 vs. 66, 53 vs. 47 and 27 vs. 24, respectively, p < 0.01). Treatment with idebenone also increased blastocyst cryosurvival rates (96% vs. 78%, p < 0.01) and implantation rates following embryo transfer (35% vs. 18%, p < 0.01). Placental weights were smaller (107 mg vs. 138 mg, p < 0.05), resulting in a larger fetal to placental weight ratio (8.3 vs. 6.3, p = 0.07) after sperm idebenone treatment. Increased sperm ROS concentrations associated with advanced paternal age are reduced with the addition of idebenone in vitro, and are associated with improved fertilization rates, embryo quality and implantation rates after IVF.

Measuring Reactive Oxygen Species in Semen for Male Preconception Care: A Scientist Perspective

“…A limiting factor of current studies is the addition of antioxidants that are not cell permeable [ 132 ], therefore, the positive effects of supplementation seen in these studies maybe more due to extrinsic ROS removal via antioxidant scavenging, as opposed to reducing sperm ROS generation and intrinsic ROS scavenging. Similar to oral antioxidant intake studies, only a few in vitro studies have examined the downstream effects on fertilization, embryo development and live birth reporting favorable outcomes [ 133 , 134 , 135 , 136 , 137 ], which are required in order to provide an evidence base prescribing use of antioxidants in clinical practice. This is important as excessive amounts of antioxidants can have the opposite effect, interfering with physiological ROS concentrations, leading to enhanced ROS generation in mitochondria and lead to further oxidative injury to cells [ 138 , 139 ].…”

Age-Related Decline of Male Fertility: Mitochondrial Dysfunction and the Antioxidant Interventions

“…Some studies have found that antioxidants can improve sperm quality in aging males [ 100 , 101 ] and some have found no improvement [ 100 ]. In addition, in vitro studies have found that adding idebenone (a mitochondrial-permeable synthetic benzoquinone that acts as an antioxidant by scavenging free electrons) to the sperm of men over 40 years old can reduce sperm ROS and improve the fertilization rate [ 102 ]. However, the sample size of these studies is small, and the combination of multiple antioxidants is generally used, which cannot effectively prove the specific mechanism of antioxidants.…”

Case Report: Abnormalities of sperm motility and morphology in a patient with Leber hereditary optic neuropathy: Improvement after idebenone therapy

“…However, such dysfunction was not reported previously in male LHON patients. In addition, it was observed that idebenone was able to promote the vitality of spermatozoa in animals ( 9 – 11 ). But, such treatment was never used before to treat male infertility due to mtDNA mutation in human.…”