Comparison between sperm parameters and chromatin in recurrent pregnancy loss couples after antioxidant therapy

The Role of Seminal Oxidative Stress in Recurrent Pregnancy Loss

Recurrent pregnancy loss is a distressing condition affecting 1–2% of couples. Traditionally investigations have focused on the female, however more recently researchers have started to explore the potential contribution of the male partner. Seminal reactive oxygen species have a physiological function in male reproduction but in excess are suspected to generate structural and functional damage to the sperm. Evidence is mounting to support an association between elevated seminal reaction oxygen species and recurrent pregnancy loss. Studies suggest that the rates of sperm DNA damage are higher in the male partners of women affected by recurrent pregnancy loss compared with unaffected men. However, the available pool of data is conflicting, and interpretation is limited by the recent change in nomenclature and the heterogeneity of study methodologies. Furthermore, investigation into the effects of oxidative stress on the epigenome show promise. The value of antioxidant therapy in the management of recurrent pregnancy loss currently remains unclear.

Alpha-Lipoic Acid Supplementation for Male Partner of Couples with Recurrent Pregnancy Loss: A Post hoc analysis in Clinical Trial

BACKGROUND

Increased sperm DNA damage is known as one of the causes of recurrent pregnancy loss (RPL) which can be due to increased levels of oxidative stress. Therefore, the aim of this study was to assess the effect of alpha-lipoic acid (ALA) on sperm parameters and sperm functions in couples with a history of RPL.

MATERIALS AND METHODS

In this post hoc analysis in clinical trial study, a total of 37 couples with RPL (n=12 and n=25 for placebo and ALA groups, respectively) were considered. Men were treated with ALA (600 mg/day) or placebo for 80 days. Semen samples were acquired from the participants before initiation and after completion of the medication course and assessed regarding conventional sperm parameters, chromatin damage/integrity, intracellular oxidative stress, lipid peroxidation, and seminal antioxidant characteristics. Individuals were further followed up for twelve months for pregnancy occurrence and outcomes. Finally, after excluding patients with no history of RPL, the data was analyzed.

RESULTS

No significant differences were observed between the baseline measures of the aforementioned parameters except for seminal volume. After the intervention, the mean sperm DNA damage, protamine deficiency, and persisted histones were significantly lower in the ALA group than in placebo receivers (P<0.05). A decrease in the mean of seminal total antioxidant capacity (P=0.03), malondialdehyde (P=0.02), and sperm DNA damage (P=0.004) as well as an increase in sperm total motility (P=0.04) after treatment with ALA was noticed. In addition, the mean of protamine deficiency and persisted histones were declined post-ALA therapy (P=0.003 and 0.002, respectively). The percentage of spontaneous pregnancy in the ALA group (4 of 25 cases; 16%) was higher than in the placebo group (1 of 12, 8.3%).

CONCLUSION

ALA-therapy attenuates sperm DNA damage and lipid peroxidation while enhancing sperm total motility and chromatin compaction in the male partner of couples with PRL (registration number: IRCT20190406043177N1).

Reactive Oxygen Species and Their Consequences on the Structure and Function of Mammalian Spermatozoa

Significance: Among the 200 or so cell types that comprise mammals, spermatozoa have an ambiguous relationship with the reactive oxygen species (ROS) inherent in the consumption of oxygen that supports aerobic metabolism. Recent Advances: In this review, we shall see that spermatozoa need the action of ROS to reach their structural and functional maturity, but that due to intrinsic unique characteristics, they are, perhaps more than any other cell type, susceptible to oxidative damage. Recent studies have improved our knowledge of how oxidative damage affects sperm structures and functions. The focus of this review will be on how genetic and epigenetic oxidative alterations to spermatozoa can have dramatic unintended consequences in terms of both the support and the suppression of sperm function. Critical Issues: Oxidative stress can have dramatic consequences not only for the spermatozoon itself, but also, and above all, on its primary objective, which is to carry out fertilization and to ensure, in part, that the embryonic development program should lead to a healthy progeny. Future Directions: Sperm oxidative DNA damage largely affects the integrity of the paternal genetic material to such an extent that the oocyte may have difficulties in correcting it. Diagnostic and therapeutic actions should be considered more systematically, especially in men with difficulties to conceive. Research is underway to determine whether the epigenetic information carried by spermatozoa is also subject to changes mediated by pro-oxidative situations. Antioxid. Redox Signal. 37, 481-500.

Spermatozoan Metabolism as a Non-Traditional Model for the Study of Huntington’s Disease

Huntington’s Disease (HD) is a fatal autosomal dominant neurodegenerative disease manifested through motor dysfunction and cognitive deficits. Decreased fertility is also observed in HD animal models and HD male patients, due to altered spermatogenesis and sperm function, thus resulting in reduced fertilization potential. Although some pharmaceuticals are currently utilized to mitigate HD symptoms, an effective treatment that remedies the pathogenesis of the disease is yet to be approved by the FDA. Identification of genes and relevant diagnostic biomarkers and therapeutic target pathways including glycolysis and mitochondrial complex-I-dependent respiration may be advantageous for early diagnosis, management, and treatment of the disease. This review addresses the HD pathway in neuronal and sperm metabolism, including relevant gene and protein expression in both neurons and spermatozoa, indicated in the pathogenesis of HD. Furthermore, zinc-containing and zinc-interacting proteins regulate and/or are regulated by zinc ion homeostasis in both neurons and spermatozoa. Therefore, this review also aims to explore the comparative role of zinc in both neuronal and sperm function. Ongoing studies aim to characterize the products of genes implicated in HD pathogenesis that are expressed in both neurons and spermatozoa to facilitate studies of future treatment avenues in HD and HD-related male infertility. The emerging link between zinc homeostasis and the HD pathway could lead to new treatments and diagnostic methods linking genetic sperm defects with somatic comorbidities.

Impact of Vitamin C on Gene Expression Profile of Inflammatory and Anti-Inflammatory Cytokines in the Male Partners of Couples with Recurrent Pregnancy Loss

Immune system disorders and increased inflammation in the male reproductive system can lead to fetal risk in the early stages of development and implantation. Antioxidants such as vitamin C can play a protective role against sperm inflammatory reactions. This study aimed to evaluate the effect of vitamin C on the expression of inflammatory and anti-inflammatory cytokine genes in the male partners of couples with recurrent pregnancy loss. In this randomized clinical trial, twenty male partners of couples with RPL were examined for sperm parameters and expression profile of some inflammatory and anti-inflammatory cytokine genes before and after treatment with vitamin C. There was a statistically significant higher rate of normal morphology and sperm concentration in each patient before and after treatment with vitamin C (p ≤ 0.05). The mRNA levels of interleukin 6 and tumor necrosis factor-alpha were significantly decreased in the sperm of patients after treatment with vitamin C compared to before treatment. In contrast, the gene expression levels of interleukin 4 and transforming growth factor-beta showed a significant increase in the sperm of patients after treatment with vitamin C. Oral daily administration of vitamin C may be effective in the fertility potential of male partners of couples with RPL not only through the improvement of the sperm parameters but also by modulating the expression profile of inflammatory and anti-inflammatory genes. Further studies on protein levels are needed to clarify the role of TNF-⍺ and IFN-γ as a prognostic value in evaluating the recurrent abortion risk in infertile male partners. This trial is registered with IRCT20180312039059N1.

The relationship between semen factors and unexplained recurrent spontaneous abortion

BACKGROUND

The male factor may contribute to unexplained recurrent spontaneous abortion (URSA). The relationship between semen factors and URSA is largely unknown. The analysis of metabolomics which is broadly acknowledged as the omics closest to the phenotype is suitable for providing assistance in the semen parameters analysis.

METHODS

We conducted a study including couples with URSA and controls which was next combined with a meta-analysis, and finally the study included 2352 subjects on semen parameters and URSA. Metabolomics analysis was conducted to detect semen metabolic factors related to URSA in total of 106 samples including seminal plasma and sperm cells.

RESULTS

The URSA group had significantly lower total sperm count, sperm concentration, motility and normal morphology percentage. Meta-analysis next showed consistent findings. Metabolomics revealed that 4 metabolites and one pathway and 8 metabolites and one pathway were significantly associated with URSA in sperm and seminal plasma, respectively. The combination of ascorbic acid and guanine in seminal plasma and hexadecanedioic acid and pyroglutamic acid in sperm showed ability for URSA prediction.

CONCLUSION

We provided novel insights into semen indices in relation to URSA. Lower sperm number and quality might increase the risk of URSA, and oxidative stress and hormone metabolism in sperm as well as nucleic acid synthesis and oxidative stress in seminal plasma were related to URSA.