Circulating Zinc and Copper Levels are Associated with Sperm Quality in Obese Men after Metabolic Surgery: A Pilot Study

Zinc as a Modulator of Male Fertility: Interplay Between Lipid Metabolism, Oxidative Stress, and Sperm Function

Infertility is a multifaceted and pressing global health challenge, with male reproductive impairment playing a significant role in its overall burden. Zinc (Zn), a biologically indispensable trace element, is fundamental to spermatogenesis and overall male reproductive function. This narrative review explores the following aspects: (1) the mechanistic function of Zn in spermatogenesis, (2) the impact of oxidative stress on Zn status and male infertility, (3) the interplay between Zn and lipid metabolism in male reproductive physiology, (4) the relationship between Zn concentrations and semen parameters, and (5) the effects of Zn supplementation on sperm quality, alongside relevant institutional recommendations. The molecular pathways underlying Zn deficiency-induced enzymatic dysfunction, oxidative stress, and lipid homeostasis disruption remain partially elucidated, warranting further investigation into their interdependent effects on male infertility. While accumulating evidence suggests that Zn supplementation may have therapeutic potential in male infertility management, guidelines for its clinical application vary considerably across institutions and regions. To establish a clear and evidence-based framework for the function of Zn in male reproductive health, future research should prioritize determining of optimal Zn levels, the mechanistic links between Zn and lipid metabolism, and the long-term clinical outcomes of Zn supplementation in infertile populations.

Copper Deficiency: A Frequently Overlooked Complication After MBS-A Systematic Review and Meta-analysis

This study reviews the prevalence of copper (Cu) deficiency in patients for metabolic and bariatric surgery (MBS), as well as the long-term outcomes related to the prevalence of Cu deficiency after undergoing MBS. A systematic literature search and meta-analysis were conducted in PubMed, Web of Science, and Scopus for articles published by August 31, 2024. The search terms included metabolic and bariatric surgery, weight loss surgery, metabolic surgery, obesity surgery, sleeve gastrectomy, gastric banding, gastric bypass, duodenal switch, duodenojejunal bypass, copper, copper deficiency, and hypocuposemia. After PRISMA screening, 43 studies with a total of 49 patients with obesity were included in this meta-analysis. The results demonstrated that the prevalence of Cu deficiency after MBS at 1-, 2-, 3-, and 4-year follow-up was found to be 16%, 28%, 21%, and 16%, respectively. Additionally, hypocuposemia was observed to be more prevalent in patients with BPD compared with other types of surgery. Copper deficiency is frequently observed in patients following MBS, particularly those who have undergone BPD procedures. Therefore, it is imperative for patients to undergo postoperative follow-up and nutritional monitoring, along with targeted interventions.

Relative Fat Mass, A Better Predictor of Erectile Dysfunction: Insights From the NHANES 2001-2004

Obesity is a significant factor contributing to erectile dysfunction (ED). Early detection of ED generally results in improved treatment outcomes. Our study aims to elucidate the association between relative fat mass (RFM) and ED by analyzing data from the National Health and Nutrition Inspection Survey (NHANES) spanning 2001 to 2004. We used data from NHANES 2001-2004, employing weighted, multivariable-adjusted logistic regression to assess the relationship between RFM and the risk of ED. Additional analyses included subgroup analysis, smooth curve fitting, and threshold effect analysis. Subsequently, the predictive utility of RFM, body mass index (BMI), and waist circumference (WC) for ED was evaluated using the receiver operating characteristic curve and area under the curve (AUC) calculations. A total of 3,947 American male participants were included in this retrospective study within NHANES. Weighted multivariate logistic regression analysis indicated that, after adjusting for potential confounding factors, RFM was positively associated with the risk of ED (OR = 1.03, 95% CI = 1.01-1.05, p < .001). No significant saturation effects between RFM and ED were observed (all ps > .05). In addition, RFM demonstrated superior predictive capability for ED (AUC = 0.644) compared with BMI (AUC = 0.525) and WC (AUC = 0.612). Our findings suggest that higher RFM levels are associated with an increased risk of ED, highlighting its potential utility as a predictive marker for this condition.

Effects of bariatric surgery on sexual function and fertility: A narrative review

Obesity has emerged as a prevalent global health concern, with its detrimental effects on the reproductive system and sexual function garnering increasing attention. Both men and women affected by obesity face a heightened risk of fertility challenges and sexual dysfunction. Although fertility and sexual function are distinct topics, they are intricately linked and mutually influential in both medical and societal contexts. Bariatric surgery (BS) has generated promising results in alleviating sexual dysfunction and enhancing fertility, results which are often gender specific. In men, improvements in sexual function can often be attributed to weight loss and subsequent optimizations in sex hormone levels. However, improving female sexual function may be related to a range of factors beyond weight loss. Bariatric procedures have shown limited benefits for male fertility; in fact, in some situations it can even be detrimental, leading to a decrease in sperm count and quality. Conversely, BS may positively impact female fertility, improving pregnancy and neonatal outcomes. Nevertheless, it is essential to consider the potential risks related to the adverse effects of malnutrition and rapid weight loss following BS, making it advisable to wait for 12-18 months before attempting pregnancy.

Effect of laparoscopic sleeve gastrectomy on male reproductive function in Chinese men with obesity: a prospective cohort study

BACKGROUND

Obesity is a widely recognized global public health issue, and bariatric surgery has emerged as an effective intervention for alleviating obesity associated health complications. However, the impact of bariatric surgery on male reproductive function remains inconclusive in the literature. The current understanding of the impact of laparoscopic sleeve gastrectomy (LSG) on male reproductive function remains ambiguous, despite its status as the most commonly performed bariatric surgery. This prospective cohort study aimed to investigate the impact of LSG on erectile function and semen quality.

PATIENTS AND METHODS

A total of 34 obese patients were enrolled in this study and underwent LSG. Prior to the operation and at 3, 6, and 12 months postoperation, all participants were required to complete the International Index of Erectile Function-5 (IIEF-5) questionnaire and undergo a nocturnal erectile function test and semen quality analysis.

RESULTS

Within 12 months postoperation, BMI, blood lipids, and insulin resistance showed significant improvement. The IIEF-5 score increased significantly (18.88±5.97 vs. 23.78±3.19, P <0.05), and the frequency and duration of erections significantly improved compared to baseline. Sperm concentration, total motility, survival rate, and sperm morphology parameters exhibited a significant decline at 3 months but demonstrated a significant improvement at 6 and 12 months postoperation. At 12 months, sperm concentration was shown to be correlated with changes in zinc (r=0.25, P =0.033) as well as changes in testosterone (r=0.43, P =0.013).

CONCLUSIONS

LSG has beneficial effects on erectile function, despite a transient decline in semen quality at 3 months postoperatively, followed by a significant improvement at 12 months.

Trace and essential elements as vital components to improve the performance of the male reproductive system: Implications in cell signaling pathways

Successful male fertilization requires the main processes such as normal spermatogenesis, sperm capacitation, hyperactivation, and acrosome reaction. The progress of these processes depends on some endogenous and exogenous factors. So, the optimal level of ions and essential and rare elements such as selenium, zinc, copper, iron, manganese, calcium, and so on in various types of cells of the reproductive system could affect conception and male fertility rates. The function of trace elements in the male reproductive system could be exerted through some cellular and molecular processes, such as the management of active oxygen species, involvement in the action of membrane channels, regulation of enzyme activity, regulation of gene expression and hormone levels, and modulation of signaling cascades. In this review, we aim to summarize the available evidence on the role of trace elements in improving male reproductive performance. Also, special attention is paid to the cellular aspects and the involved molecular signaling cascades.

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.

The freezability of Mediterranean buffalo sperm is associated with lysine succinylation and lipid metabolism

Semen cryopreservation is used for the propagation of variety among species and domestic breeding. Mitochondria are implicated in sperm freezability, and their proteins are prone to succinylation, but the relationship between sperm freezability and mitochondrial protein succinylation is unclear. In this study, six bulls were classified as having good or poor freezability ejaculates (GFE or PFE, each 3 bulls). The fresh sperm mitochondrial membrane potential (MMP) and pan succinylation level of the two groups were first detected. Then the lysine succinylome and fatty acid content of the two groups were analyzed using label-free LC-MS/MS and GC-MS/MS in multiple reaction monitoring (MRM) modes, respectively. The results indicated that the GFE sperm had significantly higher MMPs than the PFE group (p < 0.05). A total of 1393 succinylation sites corresponding to 426 proteins were assessed and 5 succinylated peptides of the GFE group were markedly upregulated, while 3 were significantly downregulated (FC > 2.0 - < 0.5 and p-value < 0.05) when compared to the PFE group. Forty-six succinylated proteins were identified to have consistent presence/absence expression. The upregulated succinylated proteins in the GFE sperm were enriched in lipid metabolic processes. A total of 31 fatty acids were further subjected to quantitative analysis of which 23 including arachidic (C20:0), linolenic (C18:3n3), and docosahexaenoic acids (C22:6n3) were decreased in GFE sperm when compared with PFE (p < 0.05). These results suggest that lysine succinylation can potentially influence the sperm freezability of Mediterranean buffaloes through mitochondrial lipid metabolism. This novel study provides our understanding of sperm succinylation and the molecular basis for the mechanism of sperm freezability.

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.

Evaluating the Serum and Seminal Plasma Levels of Zinc and Cadmium in Smokers and Their Relation to the Semen Parameters

Cigarette smoking appears to have adverse effects of male reproductivity. The interplay between zinc and cadmium presumably plays a role in mediating toxic effects of smoking. This work was conducted to study serum and seminal plasma zinc and cadmium level in smokers compared to non-smokers. Seventy males were included: 35 smokers (group I) (smoking ˃20 cigarettes/day with mild smoking index <400) and 35 age-matched non-smokers (group II). Semen analysis was performed according to the WHO laboratory manual 2010. Atomic absorption spectrophotometer was used to detect zinc and cadmium amounts in both blood plasma and semen of any groups. Smoker group showed significantly lower sperm density, motility (P=0.001), and sperm viability (P=0.002) and higher abnormally formed sperms. Seminal zinc level was significantly lower in smokers (P=0.038).There was significant negative correlation between seminal zinc and smoking index and significant positive correlation between seminal zinc levels and sperm motility (P=0.008) and viability percentage (P=0.001). Seminal cadmium level was significantly higher in smoker (P=0.022). Significant positive correlation between seminal cadmium and both age and smoking index (P=0.003) and significant negative correlation between seminal cadmium and sperm density (P=0.005), motility (P=0.047), and viability (P=0.039). Seminal zinc level was negatively correlated to seminal cadmium level (P=0.020). Smoking has deleterious effects on semen quality hence fertility through several toxicants and chemicals. Reduced zinc levels and elevated cadmium levels were evident in smokers which have significant role in the adverse effects on the semen parameters.

Bariatric Surgery Does Not Improve Semen Quality: Evidence from a Meta-analysis

The meta-analysis aimed to explore the possible relationship between bariatric surgery and semen quality. PubMed, EMBASE, and CENTRAL were searched from database inception through October 28, 2021. Articles were eligible for inclusion if they evaluated the impact pre- and post-bariatric surgery on semen parameters. A total of 9 studies with 218 patients were found. The mean preoperative age distribution of the patients included centralized from 18 to 50 years, and the mean pre-op BMI ranged from 36.7 to 70.5 kg/m². The follow-up period ranged from 6 to 24 months. The results revealed that bariatric surgery had no significant effect on sperm volume, concentration, total count, morphology, total motility, progressive motility, viability, semen pH, and semen leukocytes. Bariatric surgery does not improve semen quality in obese males.

The relationship of plasma antioxidant levels to semen parameters: the Males, Antioxidants, and Infertility (MOXI) randomized clinical trial

PURPOSE

The understanding of the role of plasma antioxidant levels in male fertility in the USA is limited. In a secondary analysis of the Males, Antioxidants, and Infertility (MOXI) randomized clinical trial, we sought to determine whether serum levels of vitamin E (α-tocopherol), zinc, and selenium were correlated with semen parameters and couple fertility outcomes.

METHODS

This study is a secondary analysis of the MOXI clinical trial. The primary endpoints in this secondary analysis include semen parameters, and DNA fragmentation and clinical outcomes including pregnancy and live birth. Analyses were completed using Wilcoxon's rank-sum test and linear regression models.

RESULTS

At baseline, the analysis included plasma labs for vitamin E (n = 131), selenium (n = 124), and zinc (n = 128). All baseline plasma values were in the normal ranges. There was no association between selenium, zinc, or vitamin E levels and semen parameters or DNA fragmentation. Baseline antioxidant levels in the male partners did not predict pregnancy or live birth among all couples. Among those randomized to placebo, baseline male antioxidant levels did not differ between those couples with live birth and those that did not conceive or have a live birth.

CONCLUSIONS

Among men attending fertility centers in the USA, who have sufficient plasma antioxidant levels of zinc, selenium, or vitamin E, no association was observed between vitamins and semen parameters or clinical outcomes in couples with male infertility. Higher levels of antioxidants among men with circulating antioxidants in the normal range do not appear to confer benefit on semen parameters or male fertility.