One-carbon cycle support rescues sperm damage in experimentally induced varicocoele in rats

The role of the transsulfuration pathway in spermatogenesis of vitamin D deficient mice

Vitamin D deficiency is a global health problem and has been linked to defective spermatogenesis and male infertility. In this study, we aimed to investigate the main enzymes involved in the transsulfuration pathway of 1-carbon metabolism, and spermatogenesis function. Therefore, sixteen male C57 mice were addressed to a control (standard diet) or vitamin D deficient (VDD) diet for 14 weeks. The results show that compared to the standard diet, VDD increased final body weight and reduced sperm quality, caused damage to the testicular structure, and decreased the serum levels of testosterone. In addition, serum concentrations of homocysteine, vitamin B12, and sperm oxidative stress markers increased. In testicular tissues, the CBS and CSE protein levels were down-regulated whereas HO-1 was up-regulated at both mRNA and protein expression levels. Within a mice deprivation model, VDD deeply suppressed testosterone and impaired spermatogenesis with oxidative stress-mediated mechanisms. The effects of the deprivation appeared to be at least in part independent of genomic and receptor-mediated vitamin D actions and suggest a specific impairment of the alternative transsulfuration pathway.

Oxidative versus reductive stress: a delicate balance for sperm integrity

Despite the long-standing notion of "oxidative stress," as the main mediator of many diseases including male infertility induced by increased reactive oxygen species (ROS), recent evidence suggests that ROS levels are also increased by "reductive stress," due to over-accumulation of reductants. Damaging mechanisms, like guanidine oxidation followed by DNA fragmentation, could be observed following reductive stress. Excessive accumulation of the reductants may arise from excess dietary supplementation over driving the one-carbon cycle and transsulfuration pathway, overproduction of NADPH through the pentose phosphate pathway (PPP), elevated levels of GSH leading to impaired mitochondrial oxidation, or as a result NADH accumulation. In addition, lower availability of oxidized reductants like NAD⁺, oxidized glutathione (GSSG), and oxidized thioredoxins (Trx-S2) induce electron leakage leading to the formation of hydrogen peroxide (H₂O₂). In addition, a lower level of NAD⁺ impairs poly (ADP-ribose) polymerase (PARP)-regulated DNA repair essential for proper chromatin integrity of sperm. Because of the limited studies regarding the possible involvement of reductive stress, antioxidant therapy remains a central approach in the treatment of male infertility. This review put forward the concept of reductive stress and highlights the potential role played by reductive vs oxidative stress at pre-and post-testicular levels and considering dietary supplementation.

Resveratrol benefits on sperm DNA, chromatin structure and reproductive outcomes of varicocelized rats

In varicocele, the main cause of sperm DNA damage is oxidative stress (OS). Resveratrol, a polyphenol with antioxidant properties, can protect cells from injuries caused by OS. We investigated the benefits of resveratrol against reproductive damage caused by experimental varicocele induced from peripuberty. Eighty peripubertal male rats were distributed into 4 groups: sham-control (S), varicocele (V), resveratrol (R) and varicocele treated with resveratrol (VR). Varicocele was induced through the partial ligature of the left renal vein. Resveratrol was given in a daily dose of 300 mg/kg body weight (gavage). Sperm samples were collected at 100 days of age for vitality, DNA fragmentation and chromatin protamination evaluations. OS analyses were carried out. Rats from all groups were mated with healthy primiparous females for evaluation of reproductive capacity and embryonic quality. The V group showed reduction of sperm vitality, altered chromatin protamination and sperm DNA integrity and high levels of OS. The VR group showed an improvement of oxidative status, sperm vitality, DNA integrity and chromatin structure, and an enhancement in the gestational index and embryonic quality. Therefore, we showed in this experimental model that resveratrol is a promising nutraceutical adjuvant and should be deeply studied to mitigate subfertility in varicocele.

Increased de novo DNA Methylation Enzymes in Sperm of Individuals with Varicocele

Objective

Chronic genital heat-stress associated with varicocele leads to DNA hypo-methylation of spermatozoa. The objective of this study was comparing level of DNA methyl-transferases (DNMTs) in sperm of men suffering varicocele with fertile individuals.

Materials and Methods

In this case-control study, semen samples were obtained from 35 infertile men with varicocele (grade II or III) and 26 fertile men. Sperm parameters were assessed according to World Health Organization (WHO) protocol. DNMTs enzymes level were assessed by flow cytometer and fluorescence microscope. mRNAs expression of these DNMTs were also assessed by real-time reverse transcription polymerase chain reaction (RT-PCR).

Results

DNMT1 and DNMT3A proteins were mainly localized in equatorial and mid-piece regions of sperm head, respectively, while DNMT3B protein appeared to be localized mainly in equatorial and anterior regions of sperm head. In contrast to DNMT1, expression and percentage of DNMT3A and DNMT3B at RNA and protein levels were significantly higher in the varicocele group compared to the fertile group (P<0.05). In addition, significant correlations were found between sperm concentration and motility as well as DNMT1 and DNMT3B proteins levels in the infertile individuals with varicocele (P<0.05). Additionally, significant correlations were observed between abnormal sperm morphology with DNMTs proteins in the infertile individuals with varicocele.

Conclusion

Unlike DNMT1, which is involved in maintenance of DNA methylation at both RNA and protein levels, expression of de novo methylation enzymes (DNMT3A and DNMT3B) at both levels were increased in the varicocele group compared to the fertile group. Based on literature, this increase might be due to the dual roles played by DNMT3A and DNMT3B, as methyl-transferases in normal condition as well as dehydroxymethylases in stress condition, like varicocele. Although, this hypothesis needs further validation.

Deferasirox, an Iron-Chelating Agent, Improves Testicular Morphometric and Sperm Functional Parameters in a Rat Model of Varicocele

Varicocele is characterized by testicular dysfunction that originates from hyperthermia and hypoxia, leading to defects in testicular tissue and altered spermatozoa structure and function. The varicocele testis is characterized by the presence of intracellular iron deposits that contribute to the associated oxidative stress. Therefore, we tested the hypothesis that administration of an iron-chelating agent, such as deferasirox (DFX), could potentially mitigate the consequences of varicocele on testicular tissue and spermatozoa. Using a well-established rat model of varicocele (VCL), we show that treatment with DFX partially improved the structure and function of the testis and spermatozoa. In particular, sperm motility was markedly restored whereas abnormal sperm morphology was only partially improved. No significant improvement in sperm count was observed that could be associated with the proapoptotic response observed following iron chelation treatment. No reduction in oxidative damage to spermatozoa was observed since lipid peroxidation and DNA integrity were not modified. This was suggested to be a result of increased oxidative stress. Finally, we also saw no indication of attenuation of the endoplasmic reticulum/unfolded protein (ER/UPR) stress response that we recently found associated with the VCL testis in rats.

Meet-in-metabolite analysis: A novel strategy to identify connections between arsenic exposure and male infertility

BACKGROUND

Despite a trend in the use of systems epidemiology to fill the knowledge gap between risk-factor exposure and adverse outcomes in the OMICS data, such as the metabolome, seriously hindrances need to be overcome for identifying molecular connections.

OBJECTIVES

Using male infertility phenotypes and arsenic exposure, we aimed to identify intermediate biomarkers that reflect both arsenic exposure and male infertility with a meet-in-metabolite analysis (MIMA).

METHODS

Urinary arsenic levels and metabolome were measured by using inductively coupled plasma-mass spectrometry (ICP-MS) and HPLC-quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS), respectively. To identify arsenic-related metabolic markers (A-MIMA), the intermediate markers were profiled by orthogonal projections to latent structures (OPLS-DA). To detect infertility-related metabolic markers (I-MIMA), the intermediate markers were investigated by weighted gene co-expression network analysis. The key node markers, related to both A-MIMA and I-MIMA, were determined by O2PLS and defined as MIMA markers. Finally, network analysis was used to construct the MIMA-related metabolic network.

RESULTS

Twelve markers each were defined through the significant associations with arsenic exposure (A-MIMA) and/or infertility (I-MIMA), respectively. Seven of them, including acetyl-N-formyl-5-methoxykynurenamine, carnitine, estrone, 2-oxo-4-methylthiobutanoic acid, malonic acid, valine, and LysoPC (10:0), were defined through the associations with both arsenic exposure and male infertility (MIMA markers). These intermediate markers were involved majorly in oxidative stress, one-carbon metabolism, steroid hormone homeostasis, and lipid metabolism pathways. The core correlation network analysis further highlighted that testosterone is a vital link between the effect of arsenic and male infertility.

CONCLUSIONS

From arsenic exposure to male infertility, the arsenic methylation that coupled one-carbon metabolism disruption with oxidation stress may have extended its effect to fatty acid oxidation and steroidogenesis dysfunction. Testosterone is at the hub between arsenic exposure and male infertility modules and, along with the related metabolic pathways, may service as a potential surrogate marker in risk assessment for male dysfunction due to arsenic exposure.

The Effect of Daily Intake of Selenium, Vitamin E and Folic Acid on Sperm Parameters in Males with Idiopathic Infertility: A Single-Blind Randomized Controlled Clinical Trial

Background

Male infertility may originate from a wide spectrum of conditions while in 30-40 percent of cases, no significant reason can be identified. Thereby, it is recognized as male idiopathic infertility. This study was undertaken to investigate the effect of daily intake of selenium, vitamin E and folic acid on sperm parameters in males with idiopathic infertility.

Materials and Methods

Seventy infertile men were selected to participate in this single-blind, randomized controlled clinical trial using convenience sampling. They were equally divided into two groups via permuted block randomization method. The intervention group received selenium tablet (200 μg per day, oral), vitamin E capsule (400 IU per day, oral) and folic acid tablet (5 mg per day, oral).The placebo group received matching placebo for three months. Semen volume, total sperm motility, sperm concentration, progressive sperm motility, normal sperm morphology, sperm motility index (SMI) and functional sperm concentration (FSC) were assessed by sperm quality analyzer-v (SQAV) before and after the intervention. Paired t test, and independent t test were used to compare the results within and between the groups, respectively. The IBM SPSS V.16.005 was used for data analysis. A P<0.05 was considered statistically significant.

Results

After three months, according to within-group analysis, a significant difference was found in mean SMI (P=0.007) and FSC (P=0.001) in the intervention group. According to between-group analysis, no significant difference was found in mean semen volume (P=0.610), sperm concentration (P=0.126), total sperm motility (P=0.765), progressive sperm motility (P=0.767), normal sperm morph (P=0.403), SMI (P=0.556) or FSC (P=0.706) between the groups.

Conclusion

Consumption of selenium, vitamin E and folic acid in infertile men with asthenozoospermia was not effective (Registration number: IRCT2017012432153N1).

Capsaicin improves sperm quality in rats with experimental varicocele

Capsaicin is the main capsaicinoid in chilli peppers that have numerous biological and pharmaceutical roles in the body such as antioxidant, anti-inflammatory, anticarcinogenic, analgesic, counterirritant and antiarthritic properties. Numerous studies have shown increased oxidative stress in men with varicocele that is caused by dilation of the spermatic vein and increase of testicular temperature. Therefore, we aimed to assess the effect of Capsaicin on sperm parameters in rats with experimental varicocele. At first, we induced varicocele in 30 Wistar rats and, verify varicocele model only in 10 rats by assessment of sperm parameters, oxidative stress, DNA damage and persistent histone after 2 months. Of the remaining 20 varicocelised rats, half of them were treated with 2.5 mg/kg Capsaicin for two months and the other half served as control. Then, sperm tests were assessed, and the results showed that Capsaicin can restore the mean of sperm oxidative stress (38.78 ± 3.75 versus 58.37 ± 4.34; p < .05), sperm concentration (60.14 ± 7.66 versus 34.87 ± 5.78; p < .05) and motility (62.43 ± 3.10 versus 41.22 ± 5.11; p < .05) in varicocelised rats treated with Capsaicin compared to varicocelised rats that were not treat. Therefore, Capsaicin possibly with reduction of oxidative stress level could improve mean of sperm concentration and motility in varicocele condition.

Alpha-lipoic acid improves sperm motility in infertile men after varicocelectomy: a triple-blind randomized controlled trial

RESEARCH QUESTION

Does supplementation with alpha-lipoic acid (ALA) enhance sperm parameters and/or the status of sperm lipid peroxidation and DNA fragmentation in men who have undergone microsurgical repair of a varicocele?

DESIGN

Individuals with a varicocele who had undergone varicocelectomy were divided into two groups receiving either 600 mg of ALA or an identical placebo for 80 days. Semen samples obtained from the participants before surgery and after completion of the course of medication were analysed and compared. Participants, clinicians and data analysts were blinded to the randomization sequence.

RESULTS

In the ALA group, total motility (P = 0.01) and progressive motility (P = 0.002) of the spermatozoa were significantly higher compared with the placebo group after surgery. Sperm lipid peroxidation and DNA damage (assessed by sperm chromatin structure assay) showed significant decreases in both the ALA and placebo groups (P ≤ 0.02) after treatment.

CONCLUSIONS

An 80-day course of ALA medication after surgical repair improves total motility and progressive motility of the spermatozoa in individuals with a varicocele.

Endoplasmic Reticulum Stress (ER Stress) and Unfolded Protein Response (UPR) Occur in a Rat Varicocele Testis Model

Using a surgically induced varicocele rat model, we show here strong evidence that the misfolded/unfolded protein response that is part of the stress response of the endoplasmic reticulum (ER) is activated in the varicocele testis (VCL), leading to the induction of apoptosis. To support this hypothesis, it is observed that the spliced variant of the X-box protein 1 (XBP1s), resulting from the activation of the inositol-requiring enzyme 1 (IRE1) membrane sensor, is significantly more represented in VCL testicular extracts. The activation of the IRE1/XBP1s pathway is also supported by the observation that the VCL testes show an increase phosphorylation of the c-Jun-kinase (JNK) known to be one intermediate of this pathway and an increased level of caspase-3, the terminal apoptotic effector, partly explaining the apoptotic status of the VCL testis.

Integrated adrenal and testicular metabolomics revealed the protective effects of Guilingji on the Kidney-Yang deficiency syndrome rats

ETHNOPHARMACOLOGICAL RELEVANCE

Guilingji (GLJ) is a well-known traditional Chinese medicine (TCM) prescription for the treatment of Kidney-Yang deficiency syndrome (KYDS).

AIM OF THE STUDY

This study aimed to address the protective effects of GLJ against KYDS in rats with pharmacodynamic indicators and target tissues (adrenal gland and testis) metabolomics.

MATERIALS AND METHODS

The rats were injected intraperitoneally (i.p) hydrocortisone to simulate KYDS and administered orally of GLJ for 30 days. Traditional pharmacodynamic indicators (body weight, behavioral indicators, biochemical parameters and histological examination) were performed to evaluate the efficacy of GLJ. Furthermore, adrenal gland and testis metabolic profiles obtained by UHPLC-Q Exactive Orbitrap-MS coupled with multivariate analysis were conducted to explore the metabolic regulation mechanism of GLJ.

RESULTS

After administration of GLJ, the weight, levels of behavioral indicators and biochemical parameters of rats were increased compared with those of the model group, and the abnormalities of morphology in adrenal and testicular tissues were improved. Furthermore, GLJ had recovering effects via the adjustment of vitamins metabolism, which was accompanied by lipids metabolism, amino acid metabolism and nucleotides metabolism.

CONCLUSIONS

The study firstly integrated the target tissues metabolic profiles, which were complementary, and GLJ had protective effects on KYDS rats via the regulation of steroid hormone biosynthesis, oxidant-antioxidant balance and energy acquisition.

Signs of ROS-Associated Autophagy in Testis and Sperm in a Rat Model of Varicocele

Since autophagy was suspected to occur in the pathological situation of varicocele (VCL), we have attempted to confirm it here using a surgical model of varicocele-induced rats. Thirty Wistar rats were divided into three groups (varicocele/sham/control) and analyzed two months after the induction of varicocele. Testicular tissue sections and epididymal mature sperm were then monitored for classic features of varicocele, including disturbance of spermatogenesis, impaired testicular carbohydrate and lipid homeostasis, decreased sperm count, increased sperm nuclear immaturity and DNA damage, oxidative stress, and lipid peroxidation. At the same time, we evaluated the Atg7 protein content and LC3-II/LC3-1 protein ratio in testis and mature sperm cells, two typical markers of early and late cellular autophagy, respectively. We report here that testis and mature sperm show higher signs of autophagy in the varicocele group than in the control and sham groups, probably to try to mitigate the consequences of VCL on the testis and germ cells.

Micronutrients in Support to The Carbon Cycle Activate Antioxidant Defences and Reduce Sperm DNA Damage in Infertile Men Attending Assisted Reproductive Technology Programs: Clinical Trial Study

Background

Micronutrients in support to the carbon cycle were shown to reduce sperm DNA damage both in animal models and infertile men. Besides supporting DNA methylation, their positive effect may be mediated by an improved performance of the endogenous antioxidant system but this has not yet been proven in clinical settings. The present study aimed at evaluating the effects of micronutrient supplementation in infertile male partners of assisted reproductive technology (ART) resistant couples.

Materials and Methods

In this experimental clinical trial study, infertile male partners of couples resistant to at least one ART cycle, with a sperm fragmentation rate >20% (TUNEL), underwent a 4-month oral supplementation with micronutrients in support to the carbon cycle including folates, B vitamins, zinc and cysteines. Semen, sperm DNA fragmentation (TUNEL), nuclear maturation (CMA3 and blue aniline staining) and lipid peroxidation (BODIPY) were assessed before and after treatment. The couples were followed-up to record clinical outcomes.

Results

Forty-three patients completed the program but full data of pre- and post-treatment were available only for 25 patients. The treatment did not modify sperm concentration or motility but improved morphology. Nuclear maturation, DNA fragmentation and lipid peroxidation significantly improved after the treatment. Overall, 10 clinical pregnancies (23.3%) and 4 live births (9.3%) were recorded during the follow-up following expectant management (25 couples) or a new intracytoplasmic sperm injection (ICSI) cycle (18 couples).

Conclusion

The micronutrients appeared to induce both DNA methylation, resulting in improved sperm nuclear matu- ration, and antioxidant defences, resulting in less DNA fragmentation and lipid peroxidation. The clinical outcomes were aligned with a possible positive effect on reproductive function. Micronutrients could be regarded as an alternative to antioxidants in correcting oxidative damage in infertile men; however, to confirm such findings, further clinical investigations are warranted (Registration number: IRCT201510207223N6).

Follicular fat-soluble vitamins as markers of oocyte competency

The main aim of this prospective study was to investigate the effect of the concentration of fat-soluble vitamins A, D, E and K in individual follicles on oocyte quality and developmental competence. The analysis was performed on 313 follicular fluid (FF) samples from 50 patients undergoing ovarian stimulation with intracytoplasmic sperm injection. We demonstrated that the mean concentration of individual vitamins in FF correlated with their level in serum (p < 0.0001). The levels of vitamin D in FF were higher than in serum, while the opposite was observed for other analyzed vitamins. We did not observe a correlation between FF vitamin D concentration with fertilization success. However, we observed its association with embryo development status on day 3. Moreover, we showed a statistically significant negative correlation between the mean day 5 embryo score and the concentration of vitamin D in serum (rS = -0.68 p = 0.01) and follicular fluid (rS = -0.71 p = 0.01). Our study showed that FF concentration of vitamin A and E was helpful in the prediction of fertilization success of each individual oocyte. Moreover, vitamin A and E concentrations in FF were associated with status of embryo development on the third day of culture. Vitamin A was also associated with the embryo quality on day 2 and the embryo development status on day 5 after fertilization. In conclusion, a combination of FF vitamin analysis and routine morphological assessment could allow for a more accurate and sensitive method of determining embryonic developmental competence and enable the selection of a better embryo to transfer and perhaps translating into an increased chance of pregnancy.Abbreviations: in vitro fertilization: IVF; anti-Mullerian hormone: AMH; follicular fluid: FF; intracytoplasmic sperm injection: ICSI; top quality: TQ; vitamin D binding globulin level: VDBP; assisted reproductive technology: ART.

Relationship between Sperm Parameters with Sperm Function Tests in Infertile Men with at Least One Failed Cycle after Intracytoplasmic Sperm Injection Cycle

Background

Imbalance between production of reactive oxygen species (ROS) and total antioxidant capacity in testis, epididymis, and seminal fluid can eventually lead to infertility. Abnormal sperm chromatin packaging, and DNA fragmentation is considered as the main underlying causes of infertility. Therefore, we aimed to assess relationship between sperm parameters with DNA damage, protamine deficiency, persistent histones, and lipid peroxidation in infertile men with at least one failed cycle after intracytoplasmic sperm injection (ICSI).

Materials and Methods

In this experimental study, semen samples were collected from infertile men with at least one failed intracytoplasmic sperm injection (ICSI) cycle (n=20). Sperm parameters, DNA damage, protamine de- ficiency, persistent histones, and lipid peroxidation were assessed using computer-assisted sperm analysis (CASA) system, sperm chromatin structure assay (SCSA) and Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays, chromomycin A3, aniline blue, and BODIPY C11 staining, respectively.

Results

A negative significant correlation was observed between sperm concentration with percentage of sperm persistent histones (r=-0.56, P=0.02), while positive significant correlations were found between percentage of sperm persistent histones with percentage of abnormal morphology (r=0.54, P=0.02), CMA3-positive spermatozoa (r=o.6, P=0.008) and intensity of lipid peroxidation (r=0.6, P=0.01). In addition, significant correlation was observed be- tween sperm DNA damage with intensity and percentage of lipid peroxidation (r=0.62, P=0.009). Correlation between CMA3-positive spermatozoa and intensity of lipid peroxidation (r=0.5, P=0.03) were also significant.

Conclusion

Observed significant correlations between sperm functional tests in infertile men with at least one failed ICSI cycle, indicated that the reduction of oxidative stress by antioxidant supplementation may be considered as one therapy approach that can improve sperm function and increase the chance of successful clinical outcomes in next assisted reproductive cycle.

In Utero One-Carbon Metabolism Interplay and Metabolic Syndrome in Cardiovascular Disease Risk Reduction

The maternal obesogenic environment plays a role in programing the susceptibility of the fetus to postnatal non-alcoholic fatty liver disease (NAFLD), a risk factor for cardiovascular disease (CVD). NAFLD is a multisystem disease that is characterized by hepatic fat accumulation due in part to dysregulated energy metabolism network through epigenetic mechanisms such as DNA methylation. DNA methylation affects fetal programing and disease risk via regulation of gene transcription; it is affected by methyl donor nutrients such as vitamin B₁₂ , methionine, folic acid, vitamin B₆ , and choline. Although several studies have documented the role of several maternal methyl donor nutrients on obesity-induced NAFLD in offspring, currently, data are lacking on its impact on CVD risk as an endpoint. The aim of this paper is to use current knowledge to construct a postulation for the potential role of a comprehensive gestational methyl donor nutrients supplementary approach on the susceptibility of offspring to developing metabolic-syndrome-related cardiovascular complications.

Effect of aerobic exercise, low-fat and high-fat diet on the testis tissue and sperm parameters in obese and nonobese mice model

Semen quality and male fertility depend on numerous factors such as age, environment, lifestyle, physical activity, genetic background and occupation. We aimed to access the effect of aerobic exercise, low- and high-fat diet on mice testis tissue, and sperm function. Obese and nonobese male mice C57BL/6 were exposed to high fat (Hf) or low fat (Lf) and/or activity (Exe: exercise or Sed: sedentary). Finally, testicular morphometric characteristics, sperm concentration and motility (light microscopy), sperm morphology (eosin/nigrosin dye), lipid peroxidation (BODIPY C11 Probe), chromatin (acridine orange and chromomycin A3 staining) were compared within obese groups (Hf/Exe, Lf/Exe, Lf/Sed, Hf/Sed) and nonobese groups (Hf/Exe, Lf/Exe, Lf/Sed, Hf/Sed). Both exercise and diet interventions did not show any alteration in testicular morphological characteristics, sperm morphology and DNA fragmentation within both obese and nonobese groups (p > 0.05). Exercise and/or diet resulted in a significant increase in sperm concentration and motility within both groups (p < 0.05). Exercise in both groups leads to high percentage of lipid peroxidation (p < 0.05). Exercise intervention significantly improved sperm protamine deficiency within obese group (p < 0.05). We concluded that exercise intervention was more effective than diet in improvement of sperm function within obese groups.