Risk of health status worsening in primary infertile men: a prospective 10-year follow-up study

Male Fertility as a Proxy for Health

Male fertility is affected by a wide range of medical conditions that directly and indirectly affect spermatogenesis. As such, it can be useful as both an indicator of current health and a predictive factor for future health outcomes. Herein, we discuss the current literature regarding the association between male fertility and systemic health conditions and exposures. We review the connection between male fertility and genetics, medications, diet, and environmental pollutants, as well as its effects on future oncologic, cardiovascular, and autoimmune conditions. Understanding this interplay will allow more health care providers to engage in health counseling that will not only improve men's reproductive outcomes but also their overall health.

Contemporary Diagnostic Work-Up for Male Infertility: Emphasizing Comprehensive Baseline Assessment

Infertility is a prevalent issue affecting many couples during their reproductive years, with a significant number facing challenges in conceiving despite regular unprotected intercourse. Male factor infertility (MFI) contributes significantly to these cases, with a significant proportion of men lacking an identifiable etiology. As such, a thorough assessment of MFI has become increasingly vital for personalized management. This position paper from the Andrology team at IRCCS Ospedale San Raffaele emphasizes a comprehensive and individualized approach to MFI work-up, addressing the evolving challenges encountered in clinical practice. Our approach involves a thorough diagnostic work-up to identify the underlying causes of MFI, integrating insights from extensive literature review and our proprietary data. Our data demonstrates that an extensive diagnostic assessment allows us to identify at least one underlying cause of MFI in most infertile men. However, challenges persist in diagnosing less severe phenotypes with unclear etiology. We discuss the importance of individualized MFI work-up and its implications for developing rational therapeutic protocols. Lastly, this paper highlights the necessity for a personalized diagnostic assessment, addressing the daily clinical challenges and emphasizing tailored approaches to try to improve outcomes among couples seeking first medical help for infertility.

A Systematic Review and Meta-analysis on the Impact of Infertility on Men's General Health

CONTEXT

Male infertility has been associated with increased morbidity and mortality.

OBJECTIVE

To perform a systematic review and meta-analysis to provide the most critical evidence on the association between infertility and the risk of incident comorbidities in males.

EVIDENCE ACQUISITION

A systematic review and meta-analysis was performed according to the Meta-analysis of Observational Studies in Epidemiology and Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, and registered on PROSPERO. All published studies on infertile versus fertile men regarding overall mortality and risks of cancer, diabetes, and cardiovascular events were selected from a database search on PubMed, EMBASE, Google Scholar, and Cochrane. Forest plot and quasi-individual patient data meta-analysis were used for pooled analyses. A risk of bias was assessed using the ROBINS-E tool.

EVIDENCE SYNTHESIS

Overall, an increased risk of death from any cause was found for infertile men (hazard risk [HR] 1.37, [95% confidence interval {CI} 1.04-1.81], p = 0.027), and a 30-yr survival probability of 91.0% (95% CI 89.6-92.4%) was found for infertile versus 95.9% (95% CI 95.3-96.4%) for fertile men (p < 0.001). An increased risk emerged of being diagnosed with testis cancer (relative risk [RR] 1.86 [95% CI 1.41-2.45], p < 0.001), melanoma (RR 1.30 [95% CI 1.08-1.56], p = 0.006), and prostate cancer (RR 1.66 [95% CI 1.06-2.61], p < 0.001). As well, an increased risk of diabetes (HR 1.39 [95% CI 1.09-1.71], p = 0.008), with a 30-yr probability of diabetes of 25.0% (95% CI 21.1-26.9%) for infertile versus 17.1% (95% CI 16.1-18.1%) for fertile men (p < 0.001), and an increased risk of cardiovascular events (HR 1.20 [95% CI 1.00-1.44], p = 0.049), with a probability of major cardiovascular events of 13.9% (95% CI 13.3-14.6%) for fertile versus 15.7% (95% CI 14.3-16.9%) for infertile men (p = 0.008), emerged.

CONCLUSIONS

There is statistical evidence that a diagnosis of male infertility is associated with increased risks of death and incident comorbidities. Owing to the overall high risk of bias, results should be interpreted carefully.

PATIENT SUMMARY

Male fertility is a proxy of general men's health and as such should be seen as an opportunity to improve preventive strategies for overall men's health beyond the immediate reproductive goals.

Kidney function impairment in men with primary infertility: A case-control analysis

BACKGROUND

Infertile men have a worse overall health status than their fertile counterparts.

OBJECTIVE

We aimed to (1) compare kidney function in men presenting for primary couple's infertility with that of fertile men and (2) assess kidney function impairment toward sperm quality in infertile men.

MATERIALS AND METHODS

In this case-control study, 387 consecutive white-European infertile men were matched by age with 134 same-ethnicity fertile men. Complete clinical and laboratory data were available for each patient. The Chronic Kidney Disease Epidemiology Collaboration function was used for estimated glomerular filtration rate calculation. Kidney functional impairment was defined as an estimated glomerular filtration rate <90 mL/min per 1.73 m2 , according to the Kidney Disease Improving Global Outcomes criteria. Multivariable logistic regression analysis was used to (1) assess the association between kidney function impairment and infertility status and (2) investigate the association between kidney function and semen analysis abnormalities in infertile men.

RESULTS

After matching, 34 (8.8%) infertile men depicted at least a mild unknown impairment of kidney function compared to only four (3%) fertile men, with four (3%) of the infertile presenting with an overt kidney function impairment (estimated glomerular filtration rate <60 mL/min per 1.73 m2 ). There were no differences in terms of age, body mass index and rate of comorbidities between the two groups (all p > 0.05). After adjusting for major confounders, infertility status was associated with a higher risk of reduced estimated glomerular filtration rate (odds ratio 3.20; 95% confidence interval 1.21-5.2; p = 0.002). Conversely, estimated glomerular filtration rate was not associated with sperm abnormalities in infertile men.

CONCLUSIONS

Mild kidney function impairment was found in 9% of asymptomatic and unaware men presenting for primary couple's infertility investigation. This novel finding corroborates growing data on a significant association of male infertility with a poorer overall male health status and the need for tailored preventive strategies.

The Renaissance of Male Infertility Management in the Golden Age of Andrology

Infertility affects nearly 186 million people worldwide and the male partner is the cause in about half of the cases. Meta-regression data indicate an unexplained decline in sperm concentration and total sperm count over the last four decades, with an increasing prevalence of male infertility. This suggests an urgent need to implement further basic and clinical research in Andrology. Andrology developed as a branch of urology, gynecology, endocrinology, and, dermatology. The first scientific journal devoted to andrological sciences was founded in 1969. Since then, despite great advancements, andrology has encountered several obstacles in its growth. In fact, for cultural reasons, the male partner has often been neglected in the diagnostic and therapeutic workup of the infertile couple. Furthermore, the development of assisted reproductive techniques (ART) has driven a strong impression that this biotechnology can overcome all forms of infertility, with a common belief that having a spermatozoon from a male partner (a sort of sperm donor) is all that is needed to achieve pregnancy. However, clinical practice has shown that the quality of the male gamete is important for a successful ART outcome. Furthermore, the safety of ART has been questioned because of the high prevalence of comorbidities in the offspring of ART conceptions compared to spontaneous conceptions. These issues have paved the way for more research and a greater understanding of the mechanisms of spermatogenesis and male infertility. Consequently, numerous discoveries have been made in the field of andrology, ranging from genetics to several "omics" technologies, oxidative stress and sperm DNA fragmentation, the sixth edition of the WHO manual, artificial intelligence, management of azoospermia, fertility in cancers survivors, artificial testis, 3D printing, gene engineering, stem cells therapy for spermatogenesis, and reconstructive microsurgery and seminal microbiome. Nevertheless, as many cases of male infertility remain idiopathic, further studies are required to improve the clinical management of infertile males. A multidisciplinary strategy involving both clinicians and scientists in basic, translational, and clinical research is the core principle that will allow andrology to overcome its limits and reach further goals. This state-of-the-art article aims to present a historical review of andrology, and, particularly, male infertility, from its "Middle Ages" to its "Renaissance", a golden age of andrology.

High serum alpha-fetoprotein levels in primary infertile men

BACKGROUND

Alfa-fetoprotein (AFP) is a serum glycoprotein highly produced during fetal development. While AFP synthesis drops dramatically after birth, AFP production only persists or returns under specific pathological condition.

OBJECTIVE

We sought to investigate the rate of and the potential meaning of high AFP serum levels in men seeking first medical attention for couple's primary infertility.

MATERIALS AND METHODS

Socio-demographic and clinical data from 1803 non-Finnish, White-European primary infertile men were retrospectively analysed. AFP was routinely measured in each patient (high AFP was defined as >7 ng/ml). Men with history of liver diseases, testicular cancer, or other known causes of increased AFP levels were excluded from the final analysis. Semen analyses were based on the 2010 World Health Organization reference criteria. Descriptive statistics and logistic regression models tested the association between serum AFP and clinical variables. Possible nonlinear relationships were graphically explored with locally estimated scatterplot smoothing method.

RESULTS

Overall, high serum AFP level was found in 29 (1.7%) patients. Normal versus high AFP levels patients were comparable in terms of body mass index (BMI), Charlson Comorbidity Index, waist circumference, smoking habits, history of cryptorchidism, testicular volume, and serum hormones (i.e., follicle-stimulating hormone, luteinizing hormone, and total testosterone). Conversely, men with higher AFP levels were older (p = 0.02), had lower sperm concentration (p = 0.003), and were more frequently oligozoospermic and azoospermic (all p ≤ 0.03). At multivariate analysis, high AFP levels were independently associated with oligozoospermia (OR 3.79; p = 0.033) and azoospermia (OR 3.29; p = 0.006). Likewise, if AFP levels increase, patients were found to be older, with higher BMI and to have more comorbidities (all p < 0.05).

DISCUSSION

Unexplained high AFP levels account for almost 2% of cases in primary infertile patients without a previous history of associated disorders. Higher serum AFP levels are linked with aberrant sperm counts, older age, obesity, and a greater amount of comorbid conditions.

CONCLUSION

Despite the need for additional validation, these data suggest that serum AFP measurement might have a multifaceted role over the diagnostic work-up of males presenting for couple's infertility.

Initial Andrological Evaluation of the Infertile Male

Evaluation of a man presenting for couple infertility starts with obtaining a thorough medical history, and the couple's reproductive and sexual history. Semen analysis, according to World Health Organization recommendations, is the cornerstone of male partner evaluation. A comprehensive physical examination is essential for every male partner, with adequate assessment of the development of secondary sexual characteristics. However, more complex testing than semen analysis (eg, sperm DNA fragmentation index) may be required in selected cases. For men with oligozoospermia or azoospermia, a hormonal evaluation should be performed, including at least total testosterone, follicle stimulating hormone, and luteinising hormone. Genetic testing should be offered to azoospermic men and those with severe oligozoospermia. Ultrasound of the genitourinary tract can provide additional information in select cases. PATIENT SUMMARY: A complete medical history, physical examination, and semen analysis are essential components of the initial evaluation of men being assessed for infertility. The evaluation must proceed in parallel for male and female partners to optimise management for infertile couples.

Clinically Meaningful Improvements in Sperm DNA Fragmentation Severity in Infertile Men Treated with Superoxide Dismutase Supplementation: A Single-Center Experience

Background. Antioxidants are commonly used for the treatment of idiopathic male infertility. Previous studies have shown that antioxidants are able to improve sperm quality, but little is known about their impact on sperm DNA fragmentation (SDF). Preliminary findings showed that superoxide-dismutase (SOD)-based antioxidant plus hydroxytyrosol and carnosol (FertiPlus® SOD) therapy was associated with SDF improvement in a small cohort of infertile men. Therefore, we aimed to assess rates of and predictors of semen parameters and SDF improvements in infertile men treated with FertiPlus® SOD therapy (SOD+) or with other antioxidants without SOD (SOD−) in the real-life setting. Methods. Data from 60 consecutive infertile men with baseline SDF ≥ 30% and treated with SOD+ or SOD− for at least three months were analyzed. Clinical parameters and serum hormones were collected. Sperm parameters and SDF were requested at baseline and after SOD+ or SOD− treatment. Clinically meaningful SDF change after treatment was defined as SDF improvement >20% compared to baseline. Propensity score matching was performed to adjust for baseline differences between groups. Descriptive statistics were used to compare clinical and hormonal characteristics between SOD+ and SOD− groups. Semen characteristics were compared before and after treatment. Logistic regression models investigated the association between clinical variables and SDF improvement. Results. Groups were similar in terms of clinical, serum hormones and semen parameters at baseline after matching. Compared to baseline, sperm progressive motility (17 (10−36)% vs. 27 (12−41)%) and normal morphology (2 (1−6)% vs. 4 (2−6)%) significantly improved after SOD+ treatment (all p < 0.01), but not after SOD−. SDF values significantly improved after treatment in both groups, compared to the baseline evaluation (all p < 0.01). However, SDF values were lower after SOD+ than SOD− treatment (30 (22−36)% vs. 37 (31−42)%, p = 0.01). Similarly, a clinically meaningful improvement in SDF at follow-up was more frequently found after SOD+ than SOD− treatment (76.7% vs. 20.0%, p = 0.001). Multivariable logistic regression analysis showed that SOD+ treatment (OR 5.4, p < 0.001) was an independent predictor of clinically meaningful SDF improvement, after accounting for age and baseline FSH values. Conclusions. This cross-sectional study showed that, in a cohort of primary infertile men with SDF ≥ 30%, SOD-based treatment was significantly effective in improving SDF compared to antioxidants without SOD. Approximately 80% of men treated with SOD+ achieved clinically meaningful improvement in SDF after three months of treatment. Sperm progressive motility and normal morphology also improved after SOD+ therapy but not after SOD−. These results suggest that SOD+ treatment could be considered an effective option for the management of idiopathic infertile men with elevated SDF.

Single-cell transcriptome profiling reveals several LncRNAs differentially expressed in idiopathic germ cell aplasia

Mechanisms underlying severe male infertility are still largely elusive. However, recently, a single-cell transcription study by our group identified several differentially expressed coding genes in all the somatic cell types in testes of patients with idiopathic germ cell aplasia (iGCA). Here, we leverage this work by extending the analysis also to the non-coding portion of the genome. As a result, we found that 43 LncRNAs were differentially expressed in the somatic cells of these patients. Interestingly, a significant portion of the overexpressed LncRNAs was found to be a target of TAF9B, a transcription factor known to be involved in germ cell survival. Moreover, several overexpressed LncRNAs were also found to be activated in a mouse model of Sertoli cells treated with bisphenol A, a widespread environmental contaminant, long suspected to impair male fertility. Finally, a literature search for MEG3, a maternally imprinted LncRNA overexpressed as well in our patients, found it to be involved, among other things, in obesity and inflammation, known comorbidities of iGCA, ultimately suggesting that our findings deepen the understanding of the molecular insights coupled not only to the pathogenesis, but also to the clinical course of this class of patients.

The impact of different WHO reference criteria for semen analysis in clinical practice: who will benefit from the new 2021 thresholds for normal semen parameters?

Background

In 2021, the World Health Organization (WHO) has provided the latest update on processing and evaluating semen analysis.

Objectives

To assess (i) the rate of discordance in semen parameters categorization across three different WHO reference values (namely WHO21, 2010 and 1999) and (ii) the clinical differences among discordant semen analyses from a cohort of primary infertile men.

Materials and methods

Data from 788 infertile men were analyzed. Semen parameters were interpreted based on WHO21, WHO10, and WHO99 reference criteria. Pregnancy outcomes with assisted reproductive techniques (ART) were available for 110 (14%) patients. Descriptive statistics was applied to describe potential differences among the three consecutive WHO references criteria.

Results

Semen parameters categorizations were highly different across the three groups (p < 0.001). Of all, 271 (42.2%) patients had normal semen parameters according to WHO10 but were pathologic when considered with WHO21 reference criteria (namely, men with increased semen abnormalities). Infertile men with increased semen abnormalities had lower testicular volume (p < 0.001) but higher FSH (p < 0.01) and LH (p < 0.001) values than those who had no change in terms of semen parameters categorization. Negative ART outcomes were more frequently reported in men with worsening semen parameters compared with those with confirmed semen parameters at WHO21 versus WHO10 (26.8% vs. 49%, p = 0.03). Conversely, infertile men with worsening semen parameters at WHO21 versus WHO99 were similar in terms of clinical and hormonal characteristics compared with those with the same rate of semen abnormalities.

Conclusions

One out of three infertile men showed worsened semen categorization according to WHO21 versus WHO10. Infertile men with worsening of semen parameters had worse clinical and hormonal characteristics than those with confirmed numbers of semen abnormalities. Moreover, live birth rates were lower in men with worsening semen abnormalities as for WHO21.

Triglycerides/Glucose Index is Associated with Sperm Parameters and Sperm DNA Fragmentation in Primary Infertile Men: A Cross-Sectional Study

Study question: we aimed to investigate the relationship between the tyg index and both semen and hormonal characteristics in a cohort of primary infertile men. Summary answer: almost one in two primary infertile men presented with a triglycerides/glucose index (tyg) suggestive of insulin resistance (ir). overall, patients with tyg suggestive of ir showed worse clinical, hormonal, and semen parameters. What is already known: male factor infertility (MFI) is often associated with metabolic disorders such as diabetes mellitus and metabolic syndrome, where insulin resistance (IR) plays a relevant pathological role. Recently, TyG has been suggested as a user-friendly IR marker. Study Design: serum hormones and the sperm DNA fragmentation index (SDF) were measured in every patient. The semen analysis was based on 2010 WHO reference criteria. Glucose and insulin levels were measured for every man after a 12-h overnight fast, and the homeostatic model assessment index (HOMA-IR) was then calculated and categorized using a 2.6 threshold. Similarly, fasting glucose and triglycerides levels were measured and the TyG index was calculated and categorized using an 8.1 threshold. Descriptive statistics and logistic regression models tested the association between the TyG and semen and hormonal characteristics. Participants: complete demographic, clinical, and laboratory data from 726 consecutive white European primary infertile men were considered for this analysis. Main results and the role of chance: the median (IQR) age was 39 (35–43) years. A TyG and HOMA suggestive for IR was found in 339 (46.6%) and 154 (21.2%) men, respectively. During the Spearman’s test, the TyG index was highly correlated with HOMA-IR (rho = 0.46, p < 0.001). Compared to men with a normal TyG, men with TyG > 8.1 were older, had greater BMI and CCI scores, and lower total testosterone and sperm concentration, but higher DFI, and presented a greater proportion of NOA (all p < 0.01). The multivariable logistic regression analysis showed that men with TyG > 8.1 were at higher risk of SDF > 30 (OR 1.92 (CI: 1.2–2.9)) and NOA (OR 1.78 (CI: 1.1–2.8)). Wider implications of the findings: the Tyng index may act as a reliable marker of IR in the clinical work-up of primary infertile men in real-life settings.

Combined Use of Whole Exome Sequencing and CRISPR/Cas9 to Study the Etiology of Non-Obstructive Azoospermia: Demonstration of the Dispensable Role of the Testis-Specific Genes C1orf185 and CCT6B

The genetic landscape of male infertility is highly complex. It is estimated that at least 4000 genes are involved in human spermatogenesis, but only few have so far been extensively studied. In this study, we investigated by whole exome sequencing two cases of idiopathic non-obstructive azoospermia (NOA) due to severe hypospermatogenesis. After variant filtering and prioritizing, we retained for each patient a homozygous loss-of-function (LoF) variant in a testis-specific gene, C1orf185 (c.250C>T; p.Gln84Ter) and CCT6B (c.615-2A>G), respectively. Both variants are rare according to the gnomAD database and absent from our local control cohort (n = 445). To verify the implication of these candidate genes in NOA, we used the CRISPR/Cas9 system to invalidate the mouse orthologs 4930522H14Rik and Cct6b and produced two knockout (KO) mouse lines. Sperm and testis parameters of homozygous KO adult male mice were analyzed and compared with those of wild-type animals. We showed that homozygous KO males were fertile and displayed normal sperm parameters and a functional spermatogenesis. Overall, these results demonstrate that not all genes highly and specifically expressed in the testes are essential for spermatogenesis, and in particular, we conclude that bi-allelic variants of C1orf185 and CCT6B are most likely not to be involved in NOA and male fertility.

Diagnostic and therapeutic workup of male infertility: results from a Delphi consensus panel

Male factor infertility (MFI) is a rising issue worldwide with significant socioeconomic costs and negative psychological consequences for the couple. Current guidelines provide recommendations for its diagnosis and treatment but several gaps in the management of MFI are encountered in clinical practice due to the lack of available evidence in published literature. Uncertainty in the management of MFI cases leads to a high degree of variability in therapeutic approaches. We planned a Delphi consensus method to provide insights and help bridge the gaps that separate clinical guidelines from real-world practice. The Advisory Board collected 41 statements on debated topics in the management of MFI, each including multiple items designed as a 5-point Likert scale. The questionnaire was sent by e-mail to a panel of Italian experts for a first round of voting; members of the panel were later invited to a second round of voting, preceded by discussion of the "hot topics" identified in the first round. At both rounds of the Delphi consensus 68 experts participated to the voting process. After the first round 25 statements were identified as hot topics, and these underwent the second round of voting. Consensus was reached on many, but not all cases, leaving vagueness on few debated topics where decisions are unsupported by clinical studies or driven by controversial results. In conclusion, indications emerging from this large panel of experts may help guide the management of male factor infertility in clinical practice. Studies are needed to address unanswered questions left by cases for whom no consensus was reached.