Trends in global semen parameter values

Hope for male fecundity: clinically insignificant changes in semen parameters over 10 years at a single clinic while assessing an infertility population

PURPOSE

What is the trend in sperm parameters in a group of men attending a single reproductive center, over a 10-year period?

METHODS

A retrospective study was conducted on 12,188 semen samples obtained from unique individuals who attended a university reproductive clinic from 2009 to 2018, inclusively. Semen analysis was done using computer-assisted sperm analysis and verified by an andrologist. Analysis was done after dividing the dataset into two groups: above WHO 2010 lower reference limits (ARL) (N = 6325) and below the reference limits (BRL) (N = 5521).

RESULTS

Volume increased slightly (ARL, p = 0.049) before returning to baseline or was stable (BRL, p = 0.59). Sperm concentration and total count of the BRL and ARL group declined initially and then recovered slightly (p < 0.0001, in all cases). Although these changes were statistically significant, this was due to the large study population; clinically, these changes were quite mild and would not have been significant for fertility. Sperm total motility and progressive motility of both the BRL group and the ARL group increased slightly from 2009 until 2015 and then decreased back to baseline (p < 0.0001). This change offset the decrease in count seen in those years. A spurious change was observed with sperm morphology that declined after the first 2 years and remained stable thereafter (p < 0.0001, in both groups). However, this change was attributed to a contemporaneous change in the method of analyzing strict morphology which happened when the change occurred.

CONCLUSION

While statistically significant changes were found, clinically, these changes were quite mild and would not have been significant for fertility.

Men's perception and understanding of male-factor infertility in the UK

Male-factor infertility is a common but stigmatised issue, and men often do not receive the emotional support and the information they need. This study sought to understand awareness of male fertility issues compared to female fertility among the UK general male public, and also what were perceived as being the optimum methods for providing support for affected men, emotionally and through information. Men feel that male infertility is not discussed by the public as much as female infertility. Lifestyle issues that affect male fertility are not well understood, and men affected by infertility desire more support, including online, from health professionals and through peer support. Health professionals, including those in public health, could offer evidence-based programmes to reduce stigma and increase public knowledge about infertility, as well as offer emotional support to men with infertility problems.

Iranian temporal changes in semen quality during the past 22 years: A report from an infertility center

Background

Despite numerous reports about temporal changes in semen quality from all over the world, the debates continue. The latest systemic review has shown an overtime decrease in semen quality worldwide.

Objective

To assess the temporal changes in the semen quality among Iranian population referred to an infertility center.

Materials and Methods

In this retrospective cross-sectional study, semen parameters including concentration, motility, and morphology were compared between Iranian men reffered to Research and Clinical Center for Infertility, Yazd between 1990 to 1992 (group 1, n = 707) and 2010 to 2012 (group 2, n = 1108). Demographic characteristics and semen analysis were collected from the records. The effect of age on semen parameters was also investigated.

Results

Despite the increase in sperm concentration l in group 2, sperm with normal morphology decreased significantly (p < 0.001). Grade-A motility decreased (p < 0.001), grade B motility increased (p < 0.001), and grade C and D motile sperm remained constant (p = 0.303 and p = 0.315, respectively). Also, no significant correlation between the age and semen parameters were observed.

Conclusion

This study showed inconsistent temporal changes in the participant semen quality. Significant temporal decline were obtained between various semen parameters, sperm morphology and grade A motility. These results should be further evaluated by larger studies in the future.

Resveratrol-Based Multivitamin Supplement Increases Sperm Concentration and Motility in Idiopathic Male Infertility: A Pilot Clinical Study

Background. It is known that a multitude of factors may lead to male factor infertility, but still, in the majority of cases, the cause remains largely idiopathic, reflecting poor understanding of the basic process of spermatogenesis and the mechanisms involved. Resveratrol is a polyphenol compound that displays several cellular aspects mainly associated with SIRT1-pathway activation and promotion of mitochondrial enhancer activities. In several animal models, resveratrol has shown positive effects on mitochondria and membrane potential. This could explain effects on sperm concentration and motility. The aim of this study is to evaluate the effects on the semen parameters of GENANTE^®, a multivitamin supplement containing 150 mg of resveratrol/day, in patients with idiopathic infertility. Methods. This was a prospective single center clinical study. Twenty patients took a multivitamin supplement based on 150 mg of resveratrol (GENANTE^®), in the form of an oral tablet every 12 h, and were followed up at 1, 3, and 6 months after treatment. Pre- and post-treatment evaluation included history, clinical examination, semen analysis, hormonal determinations, and scrotal and prostatic ultrasound. Results. Our preliminary pilot study demonstrated that the multivitamin supplement based on resveratrol improves sperm motility (48.3% ± 13.8 vs. 59.0% ± 12.8, p = 0.0001) and concentration (22.6 × 10⁶/m^L ± 9.5 vs. 25.7 × 10⁶/mL ± 8.1, p = 0.0001) after 3 and 6 months of treatment in men with idiopathic infertility. Conclusion. Our data suggest that targeting the metabolic and energetic pathways involved in spermatogenesis and mitochondrial activity could lead to potential effects and counteract subfertility/infertility in men through a mitochondria dynamics mechanism. Trial registration number: ClinicalTrials.gov registration identifier: NCT03864198, registered on 1 January 2019.

Paraben Toxicology

Parabens now being formally declared as the American Contact Dermatitis Society (non)allergen of the year, the allergologic concerns regarding parabens raised during the past century are no longer a significant issue. The more recent toxicological concerns regarding parabens are more imposing, stemming from the gravity of the noncutaneous adverse health effects for which they have been scrutinized for the past 20 years. These include endocrine activity, carcinogenesis, infertility, spermatogenesis, adipogenesis, perinatal exposure impact, and nonallergologic cutaneous, psychologic, and ecologic effects. To assert that parabens are safe for use as currently used in the cosmetics, food, and pharmaceutical industries, all toxicological end points must be addressed. We seek to achieve perspective through this exercise: perspective for the professional assessing systemic risk of parabens by all routes of exposure. The data reviewed in this article strive to provide a balanced perspective for the consumer hopefully to allay concerns regarding the safety of parabens and facilitate an informed decision-making process. Based on currently available scientific information, claims that parabens are involved in the genesis or propagation of these controversial and important health problems are premature. Haste to remove parabens from consumer products could result in their substitution with alternative, less proven, and potentially unsafe alternatives, especially given the compelling data supporting the lack of significant dermal toxicity of this important group of preservatives.

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.

The need to improve fertility awareness

Women and men globally are delaying the birth of their first child. In the UK, the average age of first conception in women is 29 years. Women experience age-related fertility decline so it is important that men and women are well-informed about this, and other aspects of fertility. A group of UK stakeholders have established the Fertility Education Initiative to develop tools and information for children, adults, teachers, parents and healthcare professionals dedicated to improving knowledge of fertility and reproductive health.

Oestrogen action and male fertility: experimental and clinical findings

A proper balance between androgen and oestrogen is fundamental for normal male reproductive development and function in both animals and humans. This balance is governed by the cytochrome P450 aromatase, which is expressed also under spatio-temporal control. Oestrogen receptors ERα and/or ERβ, together with the membrane-associated G-protein-coupled functional ER (GPER), mediate the effects of oestrogen in the testis. Oestrogen action in male reproduction is more complex than previously predicted. The androgen/oestrogen balance and its regulation in the masculinisation programming window (MPW) during foetal life is the most critical period for the development of the male reproductive system. If this balance is impaired during the MPW, the male reproductive system may be negatively affected. Recent data from genetically modified mice and human infertile patients have shown that oestrogens may promote the engulfment of live Leydig cells by macrophages leading to male infertility. We also discuss recent data on environmental oestrogen exposure in men and rodents, where a rodent-human distinction is crucial and analyse some aspects of male fertility potentially related to impaired oestrogen/androgen balance.

Consistent age-dependent declines in human semen quality: a systematic review and meta-analysis

Reduced fertility typically occurs among women in their late 30s, but increasing evidence indicates that advanced paternal age is associated with changes in reproduction as well. Numerous studies have investigated age-based declines in semen traits, but the impact of paternal age on semen parameter values remains inconclusive. Using data from 90 studies (93,839 subjects), we conducted a systematic review and meta-analysis to quantify the effect of male age on seven ejaculate traits (semen volume, sperm concentration, total sperm count, morphology, total motility, progressive motility and DNA fragmentation). Age-associated declines in semen volume, percentage motility, progressive motility, normal morphology and unfragmented cells were statistically significant and results generally seemed to be robust against confounding factors. Unexpectedly, sperm concentration did not decline with increasing male age, even though we found that sperm concentration declined over time. Our findings indicate that male age needs more recognition as a potential contributor to the negative pregnancy outcomes and reduced offspring health associated with delayed first reproduction. We suggest that greater focus on collection of DNA fragmentation and progressive motility in a clinical setting may lead to better patient outcomes during fertility treatments of aging couples.

Maternal LPS exposure during pregnancy impairs testicular development, steroidogenesis and spermatogenesis in male offspring

Lipopolysaccharide (LPS) is associated with adverse developmental outcomes including embryonic resorption, fetal death, congenital teratogenesis and fetal growth retardation. Here, we explored the effects of maternal LPS exposure during pregnancy on testicular development, steroidogenesis and spermatogenesis in male offspring. The pregnant mice were intraperitoneally injected with LPS (50 µg/kg) daily from gestational day (GD) 13 to GD 17. At fetal period, a significant decrease in body weight and abnormal Leydig cell aggregations were observed in males whose mothers were exposed to LPS during pregnancy. At postnatal day (PND) 26, anogenital distance (AGD), a sensitive index of altered androgen action, was markedly reduced in male pups whose mothers were exposed to LPS daily from GD13 to GD 17. At PND35, the weight of testes, prostates and seminal vesicles, and serum testosterone (T) level were significantly decreased in LPS-treated male pups. At adulthood, the number of sperm was significantly decreased in male offspring whose mothers were exposed to LPS on GD 13-17. Maternal LPS exposure during gestation obviously diminished the percent of seminiferous tubules in stages I-VI, increased the percent of seminiferous tubules in stages IX-XII, and caused massive sloughing of germ cells in seminiferous tubules in mouse testes. Moreover, maternal LPS exposure significantly reduced serum T level in male mice whose mothers were exposed to LPS challenge during pregnancy. Taken together, these results suggest that maternal LPS exposure during pregnancy disrupts T production. The decreased T synthesis might be associated with LPS-induced impairments for spermatogenesis in male offspring.

Persistent environmental pollutants and couple fecundity: an overview

Speculation has arisen that human fecundity may be declining, possibly a function of exposure to persistent environmental chemicals that resist degradation resulting in various pathways for human exposure. In contrast to considerable animal evidence suggesting adverse effects of such chemicals on reproduction, limited human research has been undertaken. To date, available data stem largely from ten unique study cohorts that have quantified individual chemical exposures in relation to time-to-pregnancy (TTP), which is a measure of couple fecundity. Diminished fecundability odds ratios indicative of longer TTP were observed in all but two studies, although not all findings achieved statistical significance. Persistent chemicals associated with reduced couple fecundity as measured by a longer TTP included βHCH, cadmium, lead, mercury, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene, TCCD dioxin, and select polybrominated diethers, polychlorinated biphenyls, and perfluorochemicals. Important methodologic limitations need to be considered in weighing the evidence: i) reliance on pregnant women, which may exclude women with the highest exposures if related to the inability to conceive; ii) retrospectively reported TTP, which may be associated with bidirectional reporting errors; and iii) limited attention to male partners or couples' exposures. While current evidence is not inconsistent with animal evidence, concerted efforts to address lingering data gaps should include novel strategies for recruiting couples, the longitudinal measurement of TTP, and the continued enrollment of couples across successive pregnancies. This latter strategy will provide a more complete understanding of the toxicokinetics of chemicals during sensitive windows and their implications for fecundity and its related impairments.

Human spermatozoa: revelations on the road to conception

Human spermatozoa are highly complex specialized cells designed to survive a long and perilous journey from the site of insemination to the upper reaches of the female reproductive tract where fertilization occurs. During this journey, these cells have to run the gauntlet laid down by the female immune system and time their physiological maturation so that as soon as an egg appears in the Fallopian tube, they are equipped to recognize this cell and participate in a remarkable cascade of cellular interactions culminating in fertilization. Despite their high level of specialization, human spermatozoa are notoriously inadequate and appear to be major contributors to the poor fertility that characterizes our species. Defective spermatozoa are also known to have a major impact on the progress of pregnancy and the health trajectory of the offspring, resulting in paternally mediated increases in miscarriage rate and a range of diseases in the progeny, including dominant genetic diseases and cancer. The causes of defective sperm function are complex and involve both genetic and environmental impacts, as well as paternal age. Where genetic factors are involved, there is a concern that the widespread use of assisted conception technologies will serve to enhance the retention of poor fertility genes in the population such that the more we use assisted reproductive technologies in one generation the more we shall need them in the next. These observations may have important implications for the health and well-being of children and for the provision of reproductive healthcare services for future generations.

The epidemiology of male infertility

The purpose of this review is to integrate understanding of epidemiology and infertility. A primer on epidemiologic science and an example disease for which the design of epidemiologic investigations is readily apparent are provided. Key features of infertility that limit epidemiologic investigation are described and a survey of available data on the epidemiology of infertility provided. Finally, the work that must be completed to move this area of research forward is proposed, and, with this new perspective of "infertility as a disease," improvements envisioned in public health that may be gained through improved understanding of the epidemiology of male infertility.