Lewis S.E.M.,Queens University of Belfast |
Aitken R.J.,University of Newcastle |
Conner S.J.,University of Birmingham |
De Iuliis G.,University of Newcastle |
And 5 more authors.
Reproductive BioMedicine Online
Sperm DNA damage is a useful biomarker for male infertility diagnosis and prediction of assisted reproduction outcomes. It is associated with reduced fertilization rates, embryo quality and pregnancy rates, and higher rates of spontaneous miscarriage and childhood diseases. This review provides a synopsis of the most recent studies from each of the authors, all of whom have major track records in the field of sperm DNA damage in the clinical setting. It explores current laboratory tests and the accumulating body of knowledge concerning the relationship between sperm DNA damage and clinical outcomes. The paper proceeds to discuss the strengths, weaknesses and clinical applicability of current sperm DNA tests. Next, the biological significance of DNA damage in the male germ line is considered. Finally, as sperm DNA damage is often the result of oxidative stress in the male reproductive tract, the potential contribution of antioxidant therapy in the clinical management of this condition is discussed. DNA damage in human spermatozoa is an important attribute of semen quality. It should be part of the clinical work up and properly controlled trials addressing the effectiveness of antioxidant therapy should be undertaken as a matter of urgency. © 2013, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved. Source
Gharagozloo P.,CellOxess LLC |
Gutierrez-Adan A.,INIA |
Champroux A.,University Blaise Pascal |
Noblanc A.,University Blaise Pascal |
And 9 more authors.
STUDY QUESTION Does a novel antioxidant formulation designed to restore redox balance within the male reproductive tract, reduce sperm DNA damage and increase pregnancy rates in mouse models of sperm oxidative stress? SUMMARY ANSWER Oral administration of a novel antioxidant formulation significantly reduced sperm DNA damage in glutathione peroxidase 5 (GPX5), knockout mice and restored pregnancy rates to near-normal levels in mice subjected to scrotal heat stress. WHAT IS KNOWN ALREADY Animal and human studies have documented the adverse effect of sperm DNA damage on fertilization rates, embryo quality, miscarriage rates and the transfer of de novo mutations to offspring. Semen samples of infertile men are known to be deficient in several key antioxidants relative to their fertile counterparts. Antioxidants alone or in combination have demonstrated limited efficacy against sperm oxidative stress and DNA damage in numerous human clinical trials, however these studies have not been definitive and an optimum combination has remained elusive. STUDY DESIGN, SIZE, DURATION The efficacy of the antioxidant formulation was evaluated in two well-established mouse models of oxidative stress, scrotal heating and Gpx5 knockout (KO) mice, (n = 12 per experimental group), by two independent laboratories. Mice were provided the antioxidant product in their drinking water for 2-8 weeks and compared with control groups for sperm DNA damage and pregnancy rates. PARTICIPANTS/MATERIALS, SETTING, METHODS In the Gpx5 KO model, oxidative DNA damage was monitored in spermatozoa by immunocytochemical detection of 8-hydroxy-2′-deoxyguanosine (8OHdG). In the scrotal heat stress model, male fertility was tested by partnering with three females for 5 days. The percentage of pregnant females, number of vaginal plugs, resorptions per litter, and litter size were recorded. MAIN RESULTS AND ROLE OF CHANCE Using immunocytochemical detection of 8OHdG as a biomarker of DNA oxidation, analysis of control mice revealed that around 30% of the sperm population was positively stained. This level increased to about 60% in transgenic mice deficient in the antioxidant enzyme, GPX5. Our results indicate that an 8 week pretreatment of Gpx5 KO mice with the antioxidant formulation provided complete protection of sperm DNA against oxidative damage. In mouse models of scrotal heat stress, only 35% (19/54) of female mice became pregnant resulting in 169 fetuses with 18% fetal resorption (30/169). This is in contrast to the antioxidant pretreated group where 74% (42/57) of female mice became pregnant, resulting in 427 fetuses with 9% fetal resorption (38/427). In both animal models the protection provided by the novel antioxidant was statistically significant (P < 0.01 for the reduction of 8OHdG in the spermatozoa of Gpx5 KO mice and P < 0.05 for increase in fertility in the scrotal heat stress model). LIMITATIONS, REASONS FOR CAUTION It was not possible to determine the exact level of antioxidant consumption for each mouse during the treatment period. WIDER IMPLICATIONS OF THE FINDINGS Recent clinical studies confirm moderate to severe sperm DNA damage in about 60% of all men visiting IVF centers and in about 80% of men diagnosed with idiopathic male infertility. Our results, if confirmed in humans, will impact clinical fertility practice because they support the concept of using an efficacious antioxidant supplementation as a preconception therapy, in order to optimize fertilization rates, help to maintain a healthy pregnancy and limit the mutational load carried by children. STUDY FUNDING/COMPETING INTEREST(S) The study was funded by the Clermont Universite and the University of Madrid. P.G. is the Managing Director of CellOxess LLC, which has a commercial interest in the detection and resolution of oxidative stress. A.M. and A.P. are employees of CellOxess, LLC. J.R.D., A.G.-A. and R.J.A. are honorary members of the CellOxess advisory board. © 2016 The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. Source
Gharagozloo P.,CellOxess LLC |
Aitken R.J.,University of Newcastle
Oxidative stress in the male germ line is thought to affect male fertility and impact upon normal embryonic development. Accordingly, fertility specialists are actively exploring the diagnosis of such stress in spermatozoa and evaluating the possible use of antioxidants to ameliorate this condition. In this review, evidence for the presence of oxidative stress in human spermatozoa, the origins of this phenomenon, its clinical significance in the aetiology of male infertility and recent advances in Methods: for its diagnosis and treatment are re-examined. Moreover, an extensive review of the Results: presented in published clinical studies has been conducted to evaluate the overall impact of oral antioxidants on measures of sperm oxidative stress and DNA damage. Administration of antioxidants to infertile men has been assessed in numerous clinical studies with at least 20 reports highlighting its effect on measures of oxidative stress in human spermatozoa. A qualitative but detailed review of the Results: revealed that 19 of the 20 studies conclusively showed a significant reduction relating to some measure of oxidative stress in these cells. Strong evidence also supports improved motility, particularly in asthenospermic patients. However, of these studies, only 10 reported pregnancy-related outcomes, with 6 reporting positive associations. Adequately powered, placebo-controlled comprehensive clinical trials are now required to establish a clear role for antioxidants in the prevention of oxidative stress in the male germ line, such that the clinical utility of this form of therapy becomes established once and for all. © 2011 The Author. Source
CellOxess LLC | Date: 2011-01-03
Nutraceuticals for the treatment of Sperm Oxidative Stress and DNA damage; Nutraceuticals for use as a dietary supplement; Nutraceuticals for use as a dietary supplement for pre-conception fertility enhancement in men.
Moazamian R.,University of Newcastle |
Moazamian R.,Hunter Medical Research Institute |
Moazamian R.,CellOxess LLC |
Polhemus A.,University of Newcastle |
And 12 more authors.
Molecular Human Reproduction
Oxidative stress is known to compromise human sperm function and to activate the intrinsic apoptotic cascade in these cells.One of the key features of oxidatively stressed spermatozoa is the induction of a lipid peroxidation process that results in the formation of aldehydes potentially capable of disrupting sperm function through the formation of adducts with DNA and key proteins. In this study, we have examined the impact of a range of small molecular mass aldehydes generated as a consequence of lipid peroxidation on human sperm function and also compared the two most commonly formed compounds, 4-hydroxynonenal (4HNE) and malondialdehyde (MDA), for their relative ability to reflect a state of oxidative stress in these cells. Dramatic differences in the bioactivity of individual aldehydes were observed, that generally correlated with the second order rate constants describing their interaction with the model nucleophile, glutathione. Our results demonstrate that acrolein and 4HNE were the most reactive lipid aldehydes, inhibiting sperm motility while augmenting reactive oxygen species production, lipid peroxidation, oxidative DNA damage and caspase activation, in a dose-dependent manner (P < 0.001). In contrast, a variety of saturated aldehydes and the well-known marker of oxidative stress, MDA, were without effect on this cell type. While MDA was not cytotoxic per se, its generation did reflect the induction of oxidative stress in vivo and in vitro in a manner that was highly correlated with the bioactive lipid aldehyde, 4HNE. Despite such overall correlations, individual patient samples were observed in which either MDA or 4HNE predominated. Given the relative cytotoxicity of 4HNE, we propose that this aldehyde should be the preferred criterion for diagnosing oxidative stress in the male germ line. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. Source