Trace elements in seminal plasma of men from infertile couples

Electropolymerization of poly(phenol red) on laser-induced graphene electrode enhanced adsorption of zinc for electrochemical detection

We present a highly sensitive and selective electrode of laser-induced graphene modified with poly(phenol red) (P(PhR)@LIG) for measuring zinc nutrition in rice grains using square wave anodic stripping voltammetry (SWASV). The physicochemical properties of P(PhR)@LIG were investigated with scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier infrared spectroscopy (FT-IR) and Raman spectroscopy. The modified electrode demonstrated an amplified anodic stripping response of Zn2+ due to the electropolymerization of P(PhR), which enhanced analyte adsorption during the accumulation step of SWASV. Under optimized parameters, the developed sensor provided a linear range from 30 to 3000 μg L-1 with a detection limit of 14.5 μg L-1. The proposed electrode demonstrated good reproducibility and good anti-interference properties. The sensor detected zinc nutrition in rice grain samples with good accuracy and the results were consistent with the standard ICP-OES method.

Using Bayesian and weighted regression to evaluate the association of idiopathic oligoastenoteratozoospermia with seminal plasma metal mixtures

Idiopathic oligoastenoteratozoospermia (iOAT) affects 30% of infertile men of reproductive age. However, the associations between Cr, Fe, Cu, Se or Co levels and iOAT risk have not been determined. This research aimed to assess the associations between Cr, Fe, Cu, Se and Co levels as well as their mixtures in seminal plasma and the risk of iOAT and severe iOAT. Therefore, a case‒control study including 823 participants (416 iOAT patients and 407 controls) recruited from October 2021 to August 2022 at the reproductive medicine center of the First Affiliated Hospital of Anhui Medical University was conducted in Anhui, China. The concentrations of Cr, Fe, Cu, Se and Co in seminal plasma were detected via inductively coupled plasma‒mass spectrometry. Binary logistic regression models were used to assess the associations between the levels of Cr, Fe, Cu, Se and Co and the risk of iOAT and severe iOAT; additionally, Bayesian kernel machine regression (BKMR) and weighted quantile sum (WQS) regressions were performed to evaluate the joint effect of seminal plasma levels of Cr, Fe, Cu, Se and Co on the risk of iOAT and explore which elements contributed most to the relationship. We found significant associations between the concentrations of Fe, Cu and Se in seminal plasma and iOAT risk after adjusting for covariates (Fe, lowest tertile vs. second tertile: aOR = 1.86, 95% CI = 1.31, 2.64; Cu, lowest tertile vs. second tertile: aOR = 1.95, 95% CI = 1.37, 2.76; Se, lowest tertile vs. second tertile: aOR = 1.65, 95% CI = 1.17, 2.35). A lower Se concentration in seminal plasma (lowest tertile vs. second tertile: aOR = 1.84, 95% CI = 1.10, 3.10) was positively associated with the risk of severe iOAT. Additionally, we also observed an association between the concentration of Cr in seminal plasma and the risk of iOAT before adjusting for covariates (Cr, third tertile vs. lowest tertile: OR=1.44, 95% CI: 1.03, 2.02). According to the BKMR analyses, the risk of iOAT increased when the overall concentrations were less than the 25th percentile. The results from the WQS regression indicated that a negative WQS index was significantly associated with the iOAT risk, while a positive WQS index was not. Se and Fe had significant weights in the negative direction. In conclusion, lower Cu, Fe and Se levels in seminal plasma were positively associated with iOAT risk, while higher Cr levels in seminal plasma were positively associated with iOAT risk according to the single element model, and lower levels of Se were related to a greater risk of severe iOAT; when comprehensively considering all the results from BKMR and WQS regression, Fe, Se and Cr levels contributed most to this relationship.

Cobalt's role in modulating antioxidant systems and semen quality in males

The present study investigated associations between environmental exposure to cobalt (Co) and the levels of oxidative stress parameters and the antioxidant defense system in the seminal plasma of fertile males. The study population consisted of 117 healthy, non-smoking, fertile men from the southern region of Poland. The study was carried out in 2021-22. Based on the median cobalt levels in seminal plasma, subjects were divided into two groups: those with low (Co-L) and high (Co-H) cobalt concentrations. Semen parameters assessed according to WHO 2021 recommendations. After the analysis of spermiograms, observed reduction in progressive motility after 1 h was found in the Co-H group. Moreover, superoxide dismutase (SOD), glutathione S-transferase (GST) in the Co-H group had lower activity and GR higher activity. The OSI (Oxidative stress index) were higher in the group with high cobalt concentration in semen. The concentrations of redox balance parameters: TOS, TAC and OSI significantly were higher in the Co-high group as well as GR activity. Environmental exposure to cobalt decreases sperm motility in both normal and abnormal semen. The findings from this study affirm that cobalt can induce oxidative stress and alter oxidative stress markers in semen.

Involvement of Nrf2 Signaling in Lead-induced Toxicity

Nuclear factor erythroid 2-related factor 2 (Nrf2) is used as one of the main protective factors against various pathological processes, as it regulates cells resistant to oxidation. Several studies have extensively explored the relationship between environmental exposure to heavy metals, particularly lead (Pb), and the development of various human diseases. These metals have been reported to be able to, directly and indirectly, induce the production of reactive oxygen species (ROS) and cause oxidative stress in various organs. Since Nrf2 signaling is important in maintaining redox status, it has a dual role depending on the specific biological context. On the one hand, Nrf2 provides a protective mechanism against metal-induced toxicity; on the other hand, it can induce metalinduced carcinogenesis upon prolonged exposure and activation. Therefore, the aim of this review was to summarize the latest knowledge on the functional interrelation between toxic metals, such as Pb and Nrf2 signaling.

Environmental and occupational exposure to cadmium associated with male reproductive health risk: a systematic review and meta-analysis based on epidemiological evidence

There is an abundance of epidemiological evidence and animal experiments concerning the correlation between cadmium exposure and adverse male reproductive health outcomes. However, the evidence remains inconclusive. We conducted a literature search from PubMed, Embase, and Web of Science over the past 3 decades. Pooled r and 95% confidence intervals (CIs) were derived from Cd levels of the type of biological materials and different outcome indicators to address the large heterogeneity of existing literature. Cd was negatively correlated with semen parameters (r = - 0.122, 95% CI - 0.151 to - 0.092) and positively correlated with sera sex hormones (r = 0.104, 95% CI 0.060 to 0.147). Among them, Cd in three different biological materials (blood, semen, and urine) was negatively correlated with semen parameters, while among sex hormones, only blood and urine were statistically positively correlated. In subgroup analysis, blood Cd was negatively correlated with semen density, sperm motility, sperm morphology, and sperm count. Semen Cd was negatively correlated with semen concentration. As for serum sex hormones, blood Cd had no statistical significance with three hormones, while semen Cd was negatively correlated with testosterone. In summary, cadmium exposure might be associated with the risk of a decline in sperm quality and abnormal levels of sex hormones.

Pubertal lead exposure affects ovary development, folliculogenesis and steroidogenesis by activation of IRE1α-JNK signaling pathway in rat

Epidemic studies showed that lead exposures are associated with various female reproductive dysfunctions, including infertility, miscarriage, preterm delivery, and early menopause. However, the mechanism involved is still unclear. In the current study, SD rats were exposed to lead at doses of 0, 5, 25, 50 or 250 mg/L through drinking water from postnatal day 21-56. Lead exposures did not affect the body weight or ovary weight. However, the puberty initiation (ages by which vagina opens and estrous cycle occurs) was significantly delayed by as many as 5.8 and 6.8 days respectively (P < 0.05). Also, lead exposures disrupted the estrous cycles, reduced the numbers of primordial and primary follicles and increased the number of atretic follicles by adult. Furthermore, for the highest does group, serum levels of progesterone and testosterone decreased by 80.2% (P < 0.01) and 49.9% (P < 0.05) respectively, while estradiol level increased by 69.8% (P < 0.01). Western blot analyses indicated that lead exposures specifically down-regulated the expressions of steroidogenic protein STAR, CYP17A1, and HSD3B1, while up-regulated FSHR and CYP19A1. Also, the exposure stimulated the endoplasmic reticulum stress (ERS)-related IRE1α-JNK signaling pathway members. Such activation may also result in apoptosis since the death-signaling molecules CHOP and cleaved-CASP3 were up-regulated while BCL2 was down-regulated. In conclusion, lead exposure during juvenile and puberty significantly affected ovary development and functions. The effects may relate to ERS response since the 6 members related to the pathway were all consistently activated.

Elemental profiling of human semen with confirmed normozoospermia: Baseline levels for 44 elements

BACKGROUND

As a consequence of the progressive decline in human semen quality in recent decades, modern epidemiological investigations have identified several trace elements that could be responsible for this phenomenon. However, their levels in semen have not been clearly elucidated, particularly for elements present in ultra-trace levels.

METHODS

We aimed to determine the levels of 39 (ultra)trace elements and 5 macroelements in human semen samples with confirmed normozoospermia using ICP-based techniques. The research was amplified by analyzing blood samples from the same participants.

RESULTS

Among the analyzed (ultra)trace elements in semen samples, Zn is the most and Tm is the least prominent. Zn levels in semen are so high that Zn should be considered as a macroelement in this matrix. The levels of Zn, Rh, Sm, Re, Ir, Tl, Na, and Ca were significantly higher in semen, while the levels of Cu, As, Rb, Gd, Sb, Tb, Tm, Lu, K, and Fe were significantly higher in blood. Correlation analysis of the levels of 44 individual elements in paired semen and blood samples revealed positive correlations between 43 of the elements, particularly for Tl and Pt. An exception was the negative correlation for Cu, which showed that its high level in semen is associated with a low level in blood and contrariwise.

CONCLUSION

The reported data can be used as baseline levels/reference values for 44 elements in human semen. Furthermore, the findings of this study could be relevant for further consideration of male infertility.

Relation of seminal plasma trace mineral in the Arabian stallion's semen with the semen characteristics and subsequent fertility

Background

Seminal plasma contains several microelements like Zn, Fe, Se, and Cu that affect sperm motility and male fertility. Biochemical evaluation of seminal plasma trace elements is important for assessing fertility and diagnosing male infertility.

Aims

The present study was designed to evaluate the effect of seminal fluid trace elements on sperm parameters and fertility in Arabian horses.

Methods

Ninety-four ejaculates from 25 Arabian stallions (4–27 years old) were used to investigate the effect of seminal fluid trace elements on semen parameters and fertility. Data divided according to season, stallion age, and fertility of stallions. The concentrations of Zn, Fe, Se, Cu, Cr and Mo were determined using an atomic absorption spectrophotometer. Percentage stallion fertility estimated by mares that conceived on their first cycle. Data were analyzed by ANOVA using SPSS statistical software program (2013), version 22.0.

Results

There was a significant effect of season on semen volume, pH, Fe, Se, Cu, Cr, and Mo. Stallion age had a significant effect on pH, sperm motility, concentration, total motile sperm count, sperm abnormalities, Zn, and Fe. Sperm motility was higher (P < 0.05) and sperm abnormalities were lower (P < 0.05) in group IV (>70% fertility) than in group I (infertile) and group II (<50% fertility). Sperm abnormalities were low in group IV and high in groups I and II. Seminal plasma Zn and Cu levels were higher (P < 0.05) in groups III (50_70% fertility) and IV than in group I. Fe levels were lower (P < 0.05) in group IV than in groups I, II, and III. Seminal plasma Mo concentrations were higher (P < 0.05) in group III than in group I.

Conclusions

High seminal plasma concentrations of Zn, Se, Cu, and Mo and low Fe concentrations are associated with improved stallions' semen parameters and fertility.

Seminal trace elements and their relationship with sperm parameters

Male reproductive problems may derive from many reasons including the environmental toxicants which may either intaken by occupational exposure, nutrition or bad air quality. The increased exposure to these substances due to rapid industrial development and technology has raised the questions: Is there a relationship between sperm parameters and these substances, and if so, in what extent? Results of studies on the subject reported conflicting results, many of which were not investigated in the seminal plasma. The aim of the current study was to evaluate the relationship between 23 metals and trace elements in human seminal plasma and semen parameters many of which were not investigated before. Levels of 23 metals in human seminal plasma were assessed by inductively coupled plasma mass spectrometry (ICP-MS). We examined the differences between subjects with normal ejaculate (normozoospermia) and pathologic ejaculate (with at least one abnormal semen parameter) according to the WHO criteria. The only significant difference was detected for Se while the other element's difference was not statistically significant. Se was statistically significantly increased in normal semen group suggesting the positive effect of this element on semen parameters.

Association of SNPs in zinc transporter genes on seminal plasma zinc levels in humans

This study is to examine the effects of single nucleotide polymorphisms (SNPs) of SLC30A and SLC39A on seminal plasma zinc concentration. Blood and seminal plasma samples were collected from outpatients. SNPs of zinc transporters were analyzed by next Generation sequencing technology, and seminal plasma zinc concentration were determined by inductively coupled plasma optical emission spectrometry. Our date showed nine SNPs (SLC30A8 rs2466295, rs2466294, SLC30A10 c.-160 C>G, SLC39A8 rs9331, rs9705, rs151392, rs151393, SLC39A11 rs9912126, SLC39A14 rs1051708) were significantly associated with seminal plasma zinc concentration, and 14 SNPs (SLC30A8 rs2466295, rs2466294, SLC30A10 c.-160 C>G, SLC39A6 rs148550301, SLC39A8 rs9331, rs9705, rs151392, rs151393, SLC39A11 rs9912126, rs61736066, rs36041371 and SLC39A14 rs1051708, rs76963096, rs17060854) were found to be significantly associated with total zinc per ejaculate. The seminal plasma zinc concentrations and total zinc per ejaculate were associated with the number of SNPs, and decreased significantly when five SNPs (SLC39A8 rs9331, rs9705, rs151392, rs151393 and SLC39A14 rs1051708) were a combination of homozygous genotype. Our findings suggest that different zinc transporter SNPs may significantly affect seminal plasma zinc levels.

Selenium supplementation influences mice testicular selenoproteins driven by gut microbiota

Selenium is a well-known essential element with important roles in human reproductive health mainly due to its antioxidant character. This study aimed to investigate the potential role of selenoproteins on gut microbiota and male reproductive health. A new assay for the absolute quantification of selenoproteins in testicular tissue based on two dimensional chromatography with inductively coupled plasma mass spectrometry was performed for the first time. The gut microbiota profile was obtained by 16S rRNA gene sequencing. Numerous associations were found between testicular selenoproteins and gut microbiota (e.g. Mucispirillum, related with sperm activity and testosterone, was associated with glutathione peroxidase (GPx) and selenoalbumin (SeAlb), while Escherichia/Shigella, related to sex hormones, correlated with GPx, selenoprotein P (SelP) and SeAlb). The effects of Se-supplementation on testicular selenoproteins only occur in conventional mice, suggesting a potential selenoproteins-microbiota interplay that underlies testicular function. The selenoproteins GPx and SelP have been quantified for the first time in the testicles, and the novel identification of SeAlb, a protein with nonspecifically incorporated Se, is also reported. These findings demonstrate the significant impact of Se-supplementation on gut microbiota and male reproductive health. In addition, the analytical methodology applied here in selenoprotein quantification in testicular tissue opens new possibilities to evaluate their role in gut microbiota and reproductive health axis.

Cadmium Exposure and Testis Susceptibility: a Systematic Review in Murine Models

It is known that cadmium induces damage to the testis. However, the significant cadmium impact on the testicular architecture and the mechanisms involved in this process are not clear. Besides, the relationship between dose, route, and time of exposure and injuries remains poorly understood. Thus, we aimed to assess whether cadmium exposure in any dose, route, and time of exposure causes significant alteration in the testicular tissue of murine models, as well as the main mechanisms involved. We performed a structured search on the Medline/PubMed and Scopus databases to retrieve studies published until September 2018. The results were organized into an Adverse Outcome Pathway (AOP) framework. Also, a bias analysis of included studies was performed. We included 37 studies, and most of them identified significant histopathologies in both tubule and intertubule regarding routes, in a dose- and time-dependent manner. The damages were observed after the first hours of exposure, mainly vascular damages suggesting that vasculature failure is the primary mechanism. The AOP showed that potential molecular initiating events may mimic and interfere with essential elements disrupting proteins (structural and antioxidants), change in the oxidative phosphorylation enzyme activities, and gene expression alteration, which lead to reproductive failure (adverse outcome). Analysis of methodological quality showed that the current evidence is at high risk of bias. Despite the high risk of bias, cadmium triggers significant lesions in the testis of murine models, regarding routes, in a dose- and time-dependent manner, mainly due to vascular changes. Therefore, cadmium is a risk factor for male reproductive health.

Trace element analysis of human seminal plasma: A cautionary tale of preanalytical variation and use of non-traditional matrices in human biomonitoring studies

Ensuring harmonization of (ultra-)trace element measurements in non-traditional matrices is a particular analytical challenge that is highlighted in this work for seminal plasma as part of the developmental core at the Wadsworth Center Human Health Exposure Analysis Resource Targeted Laboratory. Seminal plasma was collected from 39 male partners of women undergoing in vitro fertilization and analyzed by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) following deproteinization with concentrated HNO₃. Validation was accomplished using: 1) two aqueous NIST SRMs; 2) a seminal plasma QC pool, characterized via standard additions; 3) standard additions on a subset of samples; and 4) sample duplicates. Agreement with NIST certified or reference values were obtained to within ±15% for the SRMs, and agreement between aqueous calibration values and standard additions values agreed to within ±10-20% for all elements. Standard additions of seminal plasma samples revealed varying matrix effects for Cu and Cr that were not found for the pooled samples. Duplicate analyses agreed to within ±10-30% depending on element. A potential source of contamination in colloidal silica used for processing seminal plasma was identified that requires further study. Comparisons with literature indicate lack of consensus for As, Cd, Cr, Mn, Pb, and V content in seminal plasma. Further work is needed to improve harmonization of future studies.

Impact of biological and artificial seminal fluids on sperm parameters and DNA status in asthenozoospermic ejaculates

The chemical composition and physiological properties of seminal fluid (SF) affect sperm quality. The objective was to investigate the effects of in vitro exposure of artificial seminal fluid (ASF) and biological seminal fluid (SF) on sperm quality. Asthenozoospermic ejaculates (n = 20) were divided into two aliquots. The first aliquot was centrifuged for obtaining asthenozoospermic SF. The second aliquot was processed with density gradient centrifugation (DGC), and the pellet was diluted separately with following media: (a) ASF; (b) Ham's F10; (c) normozoospermic SF; and (d) asthenozoospermic SF. Sperm parameters and DNA status were assessed after DGC, as well as 2 and 24 hr after incubation. The data showed that sperm progressive motility, viability and DNA integrity were significantly higher in ASF than Ham's F10 medium immediately after DGC. At 2 and 24 hr, the progressive motility was significantly decreased in biological SF compared with ASF and Ham's F10. DNA fragmentation index (DFI) was significantly lower in normozoospermic SF than asthenozoospermic SF and Ham's F10 at time 2 hr. In conclusion, normal SF showed the protective role on sperm DNA structure. Moreover, ASF preserved sperm motility better than biological SF during 24 hr, despite being similar to normal SF regarding DNA integrity preservation in short time.

Cyanidin-3-O-glucoside restores spermatogenic dysfunction in cadmium-exposed pubertal mice via histone ubiquitination and mitigating oxidative damage

Cadmium (Cd) is an environmental contaminant found in soil, water, and food, and can cause oxidative stress and male reproductive damage. During puberty, the male reproductive system is very vulnerable to interference, however, the dysregulation of Cd on spermatogenesis in this period is ambiguous. The anthocyanin cyanidin-3-O-glucoside (C3G) is phytochemical rich in plants and fruits and has been shown to have remarkable anti-oxidant activity, making it an ideal nutrient for nutritional intervention. By modeling Cd-induced damage in male pubertal mice and feeding with C3G, we demonstrated that the C3G could rescue the amount and activity of sperm predominantly. Furthermore, C3G showed partial resistance to Cd-induced histone modification during spermiogenesis and prevented oxidative damage of the DNA in the sperm nucleus. Additionally, C3G mitigated the oxidative stress of testis to achieve the level coinciding with the control group. Meanwhile, Cd-induced mitochondrial apoptosis of sperm cells was reduced significantly via the MAPK signaling pathway in the presence of C3G. Collectively, our findings can offer a potential intervention for combating Cd-induced reproductive damage during puberty by taking anthocyanin as a dietary supplement.

Cadmium in Seminal Plasma of Fertile and Infertile Male Dromedary Camels

The objective of this study was to investigate the cadmium (Cd) profile in seminal plasma of male dromedary camel with impotentia generandi (post-coital infertility, IG group, n = 14) in comparison with known fertile males (FERT group, n = 5). Andrological examination was carried out for all animals. Semen was collected with electroejaculation and examined for volume, concentration, motility, viability, and abnormality. Seminal fluid was harvested after centrifugation and analyzed for Cd using atomic absorption spectrophotometer. Results showed that sperm concentration, motility, and viability were higher, while sperm abnormality was lower in IG group than in FERT group (P < 0.05). Cd was higher in seminal plasma of IG group than in FERT group (P = 0.04). Negative correlation was found between Cd concentration and sperm concentration (r = - 0.511, P = 0.04). There was also a tendency for negative correlation between Cd concentration and the testicular size (r = - 0.455, P = 0.05). In conclusion, Cd may be one of factors causing infertility in male dromedary camels.

An overview on role of some trace elements in human reproductive health, sperm function and fertilization process

Human semen contains several trace elements such as calcium (Ca), copper (Cu), manganese (Mn), magnesium (Mg), zinc (Zn) and selenium (Se) which are necessary for reproductive health, normal spermatogenesis, sperm maturation, motility and capacitation, as well as normal sperm function. In this review, the potential role of these trace elements in male reproductive health, normal function of spermatozoa and fertility potency were considered. We selected and reviewed articles that considered crucial roles of trace elements in human sperm function and fertility. Ca is essential for sperm motility and its hyperactivation, sperm capacitation and acrosome reaction, as well as sperm chemotaxis. Sodium (Na) and potassium (K) are involved in sperm motility and capacitation. Mg is necessary for normal ejaculation, spermatogenesis and sperm motility. Zn is one of the most significant nutrients in human semen. Seminal deficiency of Zn can be associated with delayed testicular development, impaired spermatogenesis, deficiency of sex hormones, oxidative stress and inflammation, and apoptosis. Se is another significant element which has antioxidative properties and is essential for spermatogenesis and the maintenance of male fertility. Mn is a potent stimulator for sperm motility; however, increased level of seminal plasma Se can be toxic for sperm. Like Se, Cu has antioxidative properties and has a positive effect on sperm parameters. Decreased level of these trace elements can negatively affect human reproductive health, semen quality, sperm normal function and as the result, fertility potency in men. Measurement of these trace elements in men with idiopathic infertility is necessary.

Logistic Regression Analysis Factors Affecting Sperm Motility and Abnormal Sperm Morphology in Boars

Simple Summary

Reduced sperm motility and morphological abnormalities have significant negative impacts on conception rates in sows and are important indexes of semen. The identification of factors that influence sperm motility and morphology will improve boar fertility in commercial herds. On the basis of analysis of 5042 ejaculates from 385 boars using a logistic regression model, we found that serum Cu excess, serum Fe deficiency, and Pb presence in seminal plasma were risk factors for poor semen quality in boars. More importantly, the presence of seminal plasma Pb had more serious effect on the probability of abnormal sperm morphology than serum Cu excess and serum Fe deficiency. In addition, Yorkshire and Landrace boars had higher sperm motility and lower abnormal sperm morphology than Duroc boars. The difference in serum and seminal plasma elements among boars with different semen qualities may become a guide for regulating these elements used in boar diet. The highly predictive values of serum Cu, Fe, and seminal plasma Pb could be used in the future as an additional tool in semen quality evaluation.

Abstract

Logistic regression models, including variables of boar breed, age, serum, and seminal plasma elements, were used to identify the influencing factors of sperm motility and morphology in this study. Sperm motility degree was classified as grade 0: ≤85% and grade 1: >85%. Abnormal sperm morphology was classified as grade 0: ≤10%, grade 1: 10–20%, and grade 2: >20%. Element concentration of 385 boars was detected by inductively coupled plasma mass spectrometry. Results showed that boars with serum Cu ≥ 2.5 mg/L had lower sperm motility (odds ratio (OR): 0.496; 95% confidence interval (CI): 0.285–0.864) and higher abnormal sperm morphology (OR: 2.003; 95% CI: 1.189–3.376) than those with serum Cu ≤ 2.0 mg/L. Boars with serum Fe ≥ 1.5 mg/L had lower abnormal sperm morphology than those with serum Fe ≤ 1.0 mg/L (OR: 0.463; 95% CI: 0.255–0.842). The presence of Pb in seminal plasma increased abnormal sperm morphology. The probability of abnormal sperm morphology >20% from boars with seminal plasma Pb increased with a range of 5.78–15.30% than that from boars without seminal plasma Pb among three breeds. In conclusion, serum Cu excess, serum Fe deficiency, and seminal plasma Pb are risk factors for poor semen quality in boars.

Serum and Seminal Plasma Element Concentrations in Relation to Semen Quality in Duroc Boars

Element concentrations in serum and seminal plasma were studied in Duroc boars with different semen quality characteristics. Based on the utilization rate of 2174 ejaculates from June to August in 2016, a total of 166 Duroc boars were allocated into three groups: low utilization rate group (LG, 0 to 60% utilization rate), medium utilization rate group (MG, 60 to 80%), and high utilization rate group (HG, 80 to 100%). Serum and seminal plasma samples were collected, and element levels were analyzed using inductively coupled plasma mass spectrometry. The results showed that LG boars had higher concentrations of serum copper and seminal plasma cadmium compared with MG and HG boars (P < 0.05), and serum copper and seminal plasma cadmium were negatively correlated with sperm motility, while positively correlated with the abnormal sperm rate. We observed the abnormal sperm rate increased by approximately 4.53% with serum copper increasing from 1.63 to 2.44 mg/L, while sperm motility decreased by approximately 2.85% with seminal plasma cadmium increasing from 0 to 0.82 μg/L. Moreover, serum iron and manganese levels in the LG group were significantly reduced compared with the HG boars (P < 0.05), and the two elements were negatively correlated with the abnormal sperm rate (P < 0.05). In conclusion, excessive copper and absence of iron and manganese in serum as well as higher seminal plasma cadmium may reduce the utilization rate of semen by impairing sperm motility and morphology, indicating the importance of adding and monitoring microelements in boar diet.

Microelements in seminal and serum plasma are associated with fresh semen quality in Yorkshire boars

This study aimed to explore associations between semen quality and trace element level in serum and seminal plasma in Yorkshire boars. Semen quality of 112 Yorkshire boars was assessed for 13 weeks to calculate semen utilization rate, which was then divided into three categories: low utilization rate group (LG, < 60% utilization rate), medium utilization rate group (MG, 60-80%), and high utilization rate group (HG, > 80%). After grouping, serum and seminal plasma samples of selected boars were collected to determine concentrations of 10 elements including Ca, Mg, Cu, Fe, Zn, Mn, Se, Cr, Pb and Cd using inductively coupled plasma mass spectrometry. Results showed the increase of semen utilization rate was accompanied by the increase of sperm motility and the decrease of abnormal sperm rate among three groups (P < 0.01). Serum Fe concentration in LG boars was lower than that in HG boars (P < 0.05). Regression analysis revealed serum Fe concentration was positively correlated with sperm motility (r = 0.251; P < 0.05), while negatively correlated with abnormal sperm rate (r = -0.207; P < 0.05). However, MG and HG boars had lower serum Se concentration than LG boars (P < 0.05), and serum Se concentration contribution to sperm motility varied in a quadratic manner (Sperm motility = -0.0004 Se_(serum)² +0.136 Se+74.06; r = 0.300; P < 0.01). Semen utilization rate tended to decrease with the increase of seminal plasma Pb concentration (P = 0.09). Regression analysis exhibited seminal plasma Pb negatively related to sperm motility (r = -0.237; P < 0.05), while positively correlated with abnormal sperm rate (r = 0.237; P < 0.05). Furthermore, seminal plasma Pb was the most influential factor among trace element in serum and seminal plasma on sperm motility basing on the generalized linear model analysis (P < 0.05). Sperm motility decreased by approximately 3.47% when seminal plasma Pb concentration increased from 0 μg/L to 11.16 μg/L. In conclusion, deficiency of serum Fe reduces semen utilization rate by impairing sperm motility and morphology, whereas excessive serum Se decreases sperm motility. More importantly, the mere existence of seminal plasma Pb has more impact on semen quality than other trace elements in serum and seminal plasma in Yorkshire boars.

Human Sperm Characteristics with Regard to Cobalt, Chromium, and Lead in Semen and Activity of Catalase in Seminal Plasma

We analyzed cobalt (Co), chromium (Cr), and lead (Pb) concentrations in human semen and catalase CAT activity in seminal plasma and the effects of their relations on the sperm quality. We obtained semen samples from men (n = 168) undergoing routine infertility evaluation. Studies included two groups based on the ejaculate parameters: I (n = 39; normal ejaculate; normozoospermia); II (n = 129; pathological spermiogram). We examined relationships and differences between Co, Cr, and Pb concentrations in seminal plasma, CAT activity, and semen parameters. We did not establish differences in Co, Cr, and Pb concentrations and CAT activity from men between normozoospermic and those with pathological spermiogram. We found a significantly lower Co concentration and CAT activity in males with normal sperm motility than in asthenozoospermic males. We found significantly lower Co and a higher Pb concentration in males with normal morphology of spermatozoa than in teratozoospermic males. We found a significantly higher Pb concentration in the individuals with consumption of alcohol than in those without consumption. There were significant correlations between Co and Pb concentrations, sperm progressive motility (A + B, i.e., fast and slow progressive motility; Co-negatively; Pb-positively), and normal morphology of spermatozoa (Co-negatively; Pb-positively). We found a significant negative correlation between Cr concentration and slow progressive motility, and between CAT activity and volume of ejaculate. Co, Cr, and Pb levels and CAT activity were related to sperm characteristics and male fertility. The impact of alcohol may be manifested by a disturbance in Pb equilibrium in the body. Co and Pb influence progressive motility and normal morphology of human spermatozoa. Thus, Co and Pb levels in semen may be a useful diagnostic in male infertility. Most of the results of this study are in contrast to expectations. Namely, Pb is a toxic element and its harmful effects (poor semen quality) may be expected already at relatively low level of Pb exposure and are particularly visible with increasing of Pb. Co and Cr(III) are essential elements and harmful effects may be expected at their deficiency and/or overexposure.

Elemental metabolomics

Elemental metabolomics is quantification and characterization of total concentration of chemical elements in biological samples and monitoring of their changes. Recent advances in inductively coupled plasma mass spectrometry have enabled simultaneous measurement of concentrations of > 70 elements in biological samples. In living organisms, elements interact and compete with each other for absorption and molecular interactions. They also interact with proteins and nucleotide sequences. These interactions modulate enzymatic activities and are critical for many molecular and cellular functions. Testing for concentration of > 40 elements in blood, other bodily fluids and tissues is now in routine use in advanced medical laboratories. In this article, we define the basic concepts of elemental metabolomics, summarize standards and workflows, and propose minimum information for reporting the results of an elemental metabolomics experiment. Major statistical and informatics tools for elemental metabolomics are reviewed, and examples of applications are discussed. Elemental metabolomics is emerging as an important new technology with applications in medical diagnostics, nutrition, agriculture, food science, environmental science and multiplicity of other areas.

Metal/metalloid levels in urine and seminal plasma in relation to computer-aided sperm analysis motion parameters

BACKGROUND

Exposure to high levels of metals/metalloids may impair semen quality. Computer-aided sperm analysis (CASA) can be used for kinematic analysis of spermatozoa, which provides additional insights into sperm motion characteristics.

OBJECTIVE

To explore the associations of urinary and seminal plasma metal/metalloid concentrations with CASA motion parameters and assess the degree of correspondence between the two sample types.

METHODS

Eighteen metals/metalloids in seminal plasma and repeated urine samples were determined among 746 men recruited from a reproductive center. We assessed their associations with 6 CASA motion parameters [i.e., straight-line velocity (VSL), curvilinear velocity (VCL), average path velocity (VAP), linearity (LIN), straightness (STR) and amplitude head displacement (ALH)] using multivariable linear regression models.

RESULTS

We found significantly inverse dose-dependent relationships between seminal plasma arsenic (As) and VSL, VCL and VAP, between seminal plasma selenium (Se) and VSL and VAP, between seminal plasma zinc (Zn) and STR and LIN, and between seminal plasma manganese (Mn) and LIN in single-metal models [all false discovery rate (FDR) adjusted P for trend < 0.05]. These dose-response relationships remained statistically significant based on multiple-metal models and restricted cubic spline functions. Metal/metalloid concentrations in urine poorly predicted the same-day seminal plasma concentrations [coefficient of determination (R²) < 0.15]. We didn't find any significant associations between urinary metal/metalloid concentrations and the CASA motion parameters.

CONCLUSION

Exposure to high levels of As, Se, Mn and Zn may impair sperm motion capacity. Concentrations of metals/metalloids in spot urine samples cannot accurately predict same-day seminal plasma exposure levels.

Possible Mechanisms for The Effects of Calcium Deficiency on Male Infertility

Calcium (Ca) is a significant element that acts as an intracellular second messenger. It is necessary for many physiological processes in spermatozoa including spermatogenesis, sperm motility, capacitation, acrosome reaction and fertilization. Although influences of Ca deficiency on sperm function and male infertility have been widely studied, mechanisms for these abnormalities are not well considered. Poor sperm motility, impairment of chemotaxis, capacitation, acrosome reaction and steroidogenesis are the major mechanisms by which Ca deficiency induces male infertility. Therefore, an optimal seminal Ca concentration is required to strengthen sperm function and all steps leading to successful fertilization. Furthermore, identification of these mechanisms provides valuable information regarding the mechanisms of Ca deficiency on male reproductive system and the way for developing a better clinical approach. In this review, we aim to discuss the proposed cellular and molecular mechanisms of Ca deficiency on male reproductive system, sperm function and male fertility. Also we will discuss the valuable information currently available for the roles of Ca in male reproduction.

Possible Mechanisms for The Effects of Calcium Deficiency on Male Infertility

Calcium (Ca) is a significant element that acts as an intracellular second messenger. It is necessary for many physi- ological processes in spermatozoa including spermatogenesis, sperm motility, capacitation, acrosome reaction and fertilization. Although influences of Ca deficiency on sperm function and male infertility have been widely studied, mechanisms for these abnormalities are not well considered. Poor sperm motility, impairment of chemotaxis, capaci- tation, acrosome reaction and steroidogenesis are the major mechanisms by which Ca deficiency induces male infertil- ity. Therefore, an optimal seminal Ca concentration is required to strengthen sperm function and all steps leading to successful fertilization. Furthermore, identification of these mechanisms provides valuable information regarding the mechanisms of Ca deficiency on male reproductive system and the way for developing a better clinical approach. In this review, we aim to discuss the proposed cellular and molecular mechanisms of Ca deficiency on male reproductive system, sperm function and male fertility. Also we will discuss the valuable information currently available for the roles of Ca in male reproduction.

Effects of zinc deficiency on impaired spermatogenesis and male infertility: the role of oxidative stress, inflammation and apoptosis

Zinc (Zn) is necessary for the normal function of the male reproductive system and spermatozoa. Although influences of zinc deficiency on impaired spermatogenesis and male infertility have been widely considered, the molecular and cellular mechanisms of these abnormalities are not well understood. General abnormalities, including hypogonadism, Leydig cells damage, deficiency of sex hormone production and impaired spermatogenesis, as well as inflammation, antioxidant depletion, sperm death and male infertility can be observed during zinc deficiency. However, it is not obvious which pathways are relevant to the pathogenesis of zinc deficiency. Oxidative stress (OS) induced by reactive oxygen species is likely as the main mechanism of zinc deficiency which is associated with sperm DNA fragmentation, decrease in sperm membrane integrity, apoptosis, depletion of antioxidants, and consequently poor sperm quality and male infertility. Therefore, identification of these pathways will give valuable information regarding the mechanisms of zinc deficiency on the male reproductive system and the potential way for developing a better clinical approach. In this review, we aim to discuss the proposed cellular and molecular mechanisms of zinc deficiency on the male reproductive system, the importance of OS and mechanisms by which zinc deficiency induces OS and depletion of other antioxidants.

Impotentia generandi in male dromedary camels: FSH, LH and testosterone profiles and their association with clinical findings and semen analysis data

Impotentia generandi (IG) is a major problem in male dromedary camels. The objective of this research was to characterize the FSH, LH and testosterone profiles and their association with clinical findings and semen characteristics in IG-male dromedaries. Semen was collected by electroejaculation from camels with IG (n = 17) and from a fertile group (FERT, n = 5) and was evaluated for motility, viability, abnormality and concentration. According to their sperm counts, the IG-camels were categorized into three groups: those with normal sperm concentration (IG-NC, n = 8), those with oligospermia (IG-OLIGO, n = 5) and those with azoospermia (IG-AZOO, n = 4). Jugular blood was collected from all camels for analysis of FSH, LH and testosterone (T) concentrations. Results showed that the FSH, LH and T levels were higher in the IG-OLIGO and IG-AZOO groups than in the FERT and IG-NC groups (P < 0.05). The IG-camels with small testes showed lower sperm counts (P < 0.01) and greater FSH and T levels (P < 0.05) than the IG-camels with normal-sized testes. Inverse relationships were observed between the sperm counts and both the FSH and the LH levels (P < 0.05). In conclusion, the IG dromedary camels with oligo- and azoospermia were characterized by high serum levels of FSH, LH and T, indicating a condition of spermatogenic failure. In addition, inverse correlations were observed between these hormones and testicular size and sperm count.

Protective potential of royal jelly against cadmium-induced infertility in male rats

This study aimed to investigate the protective potential of Royal jelly (RJ) against cadmium (Cd)-induced testicular dysfunction in rats. Thirty-five adult male Wistar rats were assigned into five groups. G I; (control) injected intraperitoneally with saline, G II injected intraperitoneally with a single dose of CdCl₂ (1 mg/kg BW), G III received RJ (100 mg/kg BW/day) orally, G IV was pre-treated with RJ for 1 week then, treated with CdCl₂ , and G V was co-treated with RJ and CdCl₂ . After day 56, serum and tissue samples were collected and analysed. The results showed decreased serum testosterone, luteinising hormone (LH), follicle-stimulating hormone (FSH), superoxide dismutase, glutathione reductase, sperm motility and count while increased malondialdehyde, nitric oxide, tumour necrosis factor-α (TNF-α) and sperm abnormalities, along with a severely damaged seminiferous tubules epithelium with cytoplasmic and nuclear disruptions following Cd toxicity. Additionally, Cd stimulated testicular mRNA expression of TNF-α while inhibited those of steroidogenic acute regulatory protein, cytochrome P450 cholesterol side chain cleavage enzyme androgen binding protein, FSH-receptor, LH-receptor, androgen receptor, 3β-hydroxysteroid dehydrogenase (HSD), 17β-HSD, and cytochrome P450 17A1. These negative alterations of cadmium were greatly reduced by RJ treatment. This study concluded that RJ protects against Cd-induced testicular toxicity.

Impact of Seminal Plasma Trace Elements on Human Sperm Motility Parameters

Introduction. Human seminal plasma contains a variety of macro and trace elements including magnesium (Mg), copper (Cu), zinc (Zn), and iron (Fe) that have essential roles in normal functioning of semen and its quality. The imbalance of these elements has been reported in several pathologic and male infertility disorders. Therefore, this study aimed to determine the levels of these elements in seminal plasma samples, their relationships with each other and their impact on sperm motility.

Methods. Overall, 192 males (96 normospermic and 96 asthenospermic males) were enrolled in the study. Semen samples were collected by masturbation and computer-assisted/aided semen analysis of sperm motility was performed. The samples were centrifuged and seminal levels of Mg, Cu, Zn and Fe were measured using atomic absorption spectroscopy.

Results. The levels of Zn did not differ between the two groups, while the levels of Mg, Cu, and Fe were significantly higher in normospermic males. Fe showed a positive correlation with Mg and Cu in asthenospermic group. However, a negative relationship was found between Mg and Fe levels and between Mg and sperm concentration in the normospermic group. Fe levels were higher in the normospermic group compared to the asthenospermic group. Nevertheless, increased Fe levels caused a decrease in most of sperm motility fractions.

Conclusion: Elements play major roles in male fertility and directly affect sperm quality. According to the results of this study, the levels of Zn do not affect the sperm quality and motility, while Fe, Cu and Mg are decreased in males with sperm motility problems. Nevertheless, Fe levels can adversely affect sperm motility in normospermic men.

Identification of toxic metals in human embryonic tissues

INTRODUCTION

The cause of a significant number of miscarriages remains unexplained. There is a need to identify the potential role of environmental, dietary and lifestyle factors in the risk of pregnancy loss. The present study was the first to investigate the content of miscarried embryonic material with respect to eight metals (aluminium, cadmium, chromium, copper, manganese, nickel, lead and zinc).

MATERIAL AND METHODS

Embryonic tissue samples (n = 20) were obtained from women undergoing misoprostol-induced removal of the embryo between the 6^th and 9^th week of gestation. The content of metals was analyzed using microwave-induced nitrogen plasma atomic emission spectrometry. Based on a short questionnaire, the smoking habits, dietary patterns and place of living of the investigated women were determined.

RESULTS

The general mean content of metals (μg/g) decreased in the order copper (33.9) > manganese (24.7) > chromium (13.6) > zinc (13.3) > aluminium (6.5) > nickel (3.0) > lead (2.9) > cadmium (2.5). Profoundly increased concentrations (p < 0.05) of the toxic elements aluminium (over 5-fold), cadmium (over 2-fold) and lead (over 2-fold) were observed in samples obtained from former smoking women. The miscarried material in urban populations also revealed higher levels of cadmium (over 1.5-fold) and lead (over 2-fold) compared to that obtained from women living in rural areas (p < 0.05). No associations with age or diet were found (p > 0.05).

CONCLUSIONS

This study identified increased levels of aluminum, cadmium and lead in miscarried embryonic material and suggests some causative factors.

The environment and male reproduction: The effect of cadmium exposure on reproductive function and its implication in fertility

Cadmium is an environmental pollutant known as endocrine disruptor. Testis is particularly susceptible to cadmium, and testis injury occurs at high but even low levels of exposure. Cadmium reproductive toxicity is mediated by multiple mechanisms, including structural damage to testis vasculature and blood-testis barrier, inflammation, cytotoxicity on Sertoli and Leydig cells, oxidative stress mainly by means of mimicry and interference with essential ions, apoptosis, interference with selected signaling pathways and epigenetic regulation of genes involved in the regulation of reproductive function, and disturbance of the hypothalamus-pituitary-gonadal axis. The current review outlines epidemiological observational findings from environmental and occupational exposure in humans, and reports experimental studies in humans and animals. Lastly, a focus on the pathogenetic mechanisms of cadmium toxicity and on the specific mechanisms of cadmium sensitivity and resistance, particularly assessed in animal models, is included. Despite convincing experimental findings in animals and supporting evidences in humans identifying cadmium as reproductive toxicant, observational findings are controversial, suffering from heterogeneity of study design and pattern of exposure, and from co-exposure to multiple pollutants.

Screening of Blood Levels of Mercury, Cadmium, and Copper in Pregnant Women in Dakahlia, Egypt: New Attention to an Old Problem

Heavy metals toxicity is a prevalent health problem particularly in developing countries. Mercury and cadmium are toxic elements that have no physiologic functions in human body. They should not be present in the human body by any concentration. Copper, on the other hand, is one of the elements that are essential for normal cell functions and a deficiency as well as an excess of which can cause adverse health effects. To test blood levels of mercury, cadmium, and copper in pregnant women in Dakahlia, Egypt. Using atomic absorption spectrophotometry, blood levels of cadmium, mercury, and copper were measured in 150 pregnant women attending to the antenatal care in Mansoura University Hospital in Dakahlia governorate, Egypt. The mean ± SD of blood mercury, cadmium, and copper levels were found to be far from their levels in the population surveys carried in developed countries like United States of America (USA) and Canada. Heavy metal intoxication and accumulation is a major health hazard. Developing countries, including Egypt, still lack many of the regulatory policies and legislations to control sources of pollution exposure. This should be dealt with in order to solve this problem and limit its health consequences.

Associations of bisphenol A and polychlorinated biphenyls with spermatogenesis and steroidogenesis in two biological fluids from men attending an infertility clinic

BACKGROUND

In the testis, steroid hormones play an important role in spermatogenesis, the production of semen, and the maintenance of secondary sex characteristics and libido. They may also play a role as a target for substances called endocrine disruptors (EDs). As yet, however, no complex study has been conducted evaluating the relationships between EDs and the steroid spectrum in the plasma and seminal plasma.

OBJECTIVES

To shed more light into mechanisms of EDs and the effects of bisphenol A (BPA) and polychlorinated biphenyls (PCBs) on human spermatogenesis and steroidogenesis.

METHODS

We determined BPA and 11 steroids in the plasma and seminal plasma of 191 men with different degrees of fertility, using a newly developed liquid-chromatography mass spectrometry method. Concurrently, plasma levels of 6 congeners of PCBs, gonadotropins, selenium, zinc and homocysteine were measured. Partial correlations adjusted for age, BMI and abstinence time were performed to evaluate relationships between these analytes.

RESULTS

Seminal BPA, but not plasma BPA, was negatively associated with sperm concentration (r=-0.198; p=0.009), sperm count (r=-0.178; p=0.018) and morphology (r=-0.160; p=0.044). Divergent and sometimes opposing associations of steroids and BPA were found in both body fluids. The sum of PCB congeners was negatively associated with testosterone, free testosterone, the free androgen index and dihydrotestosterone in plasma.

CONCLUSION

BPA may negatively contribute to the final state of sperm quality. Moreover, our data indicate that BPA influences human gonadal and adrenal steroidogenesis at various steps. Environmental levels of PCBs negatively correlated with androgen levels, but surprisingly without negative effects on sperm quality.

Human exposure to endocrine disrupting chemicals and fertility: A case-control study in male subfertility patients

BACKGROUND

Dioxins, PCBs, chlorinated pesticides, brominated flame retardants, bisphenol A, triclosan, perfluorinated compounds and phthalates are known as endocrine disrupting chemicals (EDCs).

OBJECTIVES

The aim of our study was to investigate whether higher exposure to EDCs is associated with increased subfertility in men.

METHODS

We measured biomarkers of exposure in 163 men, recruited through four fertility clinics. According to WHO guidelines, we used a total motility count (TMC) of 20 million as cut-off value. We assigned patients to the case group when two semen samples - collected at least one week apart - had a TMC<20 and to the control group when both samples had a TMC≥20. To estimate the risk of subfertility and alteration in sex hormone concentrations we used multivariable-adjusted analysis, using logistic and linear regressions, respectively.

RESULTS

For an IQR increase in serum oxychlordane, the odds ratio for subfertility was 1.98 (95% CI: 1.07; 3.69). Furthermore, men with serum levels of BDE209 above the quantification limit had an odds of 7.22 (1.03; 50.6) for subfertility compared with those having values below the LOQ. Urinary levels of phthalates and triclosan were negatively associated with inhibin B and positively with LH. Urinary bisphenol A correlated negatively with testosterone levels.

CONCLUSIONS

Our study in men showed that internal body concentrations of endocrine disrupting chemicals are associated with an increased risk of subfertility together with alterations in hormone levels. The results emphasize the importance to reduce chemicals in the environment in order to safeguard male fertility.