Changes in Semen Analysis over Time: A Temporal Trend Analysis of 20 Years of Subfertile Non-Azoospermic Men.

PURPOSE: To examine trends of population-level semen quality over a 20-year period. MATERIALS AND METHODS: We performed a retrospective review of data from the andrology lab of a high volume tertiary hospital. All men with semen samples between 2000 and 2019 were included and men with azoospermia were excluded. Semen parameters were reported using the World Health Organization (WHO) 4th edition. The primary outcome of interest was changes in semen parameters over time. Generalized least squares (GLS) with restricted cubic splines were used to estimate average-monthly measurements, adjusting for age and abstinence period. Contrasts of the estimated averages based on GLS between the first and last months of collection were calculated. RESULTS: A total of 8,990 semen samples from subfertile non-azoospermic men were included in our study. Semen volume decreased over time and estimate average at the beginning and end were statistically different (p<0.001). Similarly sperm morphology decreased over time, with a statistically significant difference between estimated averages from start to finish (p<0.001). Semen pH appeared to be increasing over time, but this difference was not significant over time (p=0.060). Sperm concentration and count displayed an increase around 2003 to 2005, but otherwise remained fairly constant over time (p=0.100 and p=0.054, respectively). Sperm motility appeared to decrease over time (p<0.001). CONCLUSIONS: In a large sample of patients presenting to a single institution for fertility assessment, some aspects of semen quality declined across more than two decades. An understanding of the etiologies and driving forces of changing semen parameters over time is warranted.

Optimal timing for repeat semen analysis during male infertility evaluation.

OBJECTIVE: To assess whether the 4-week time period between semen analyses during the workup of male infertility is optimal and whether two samples are needed. DESIGN: Retrospective study. SETTING: Tertiary hospital. PATIENTS: Men whose semen samples were obtained within 90 days of each other, without known fertility intervention, treatment, and/or azoospermia. INTERVENTIONS: Semen analysis. MAIN OUTCOME MEASURES: Correlation between semen parameters and agreement among consecutive semen analyses. RESULTS: A total of 2,150 semen samples from 1,075 men were included in the analysis. The optimal correlation for volume occurred at weeks 2, 8, and 12 (r = 0.803, r = 0.802, and r = 0.821, respectively). For concentration, the correlation was maximized at weeks 1, 4, and 5 (r = 0.950, r = 0.841, and r = 0.795, respectively). Total sperm count correlated at weeks 1, 2, and 4 (r = 0.929, r = 0.727, and r = 0.808, respectively). Motility was maximally correlated at weeks 1, 10, and 13 (r = 0.711, r = 0.760, and r = 0.708, respectively). Morphology was optimally correlated at weeks 1, 2, and 9 (r = 0.935, r = 0.815, and r = 0.839, respectively). Semen volume was correlated in 55% of men, sperm concentration in 64% of men, sperm motility in 52% of men and sperm morphology 64% of men. CONCLUSIONS: Our data suggest that four weeks may not be the optimal time for repeat semen analysis and that one sample is insufficient to assess any abnormalities in the result of semen analysis. The optimal time between repeat semen analyses should be individualized depending on the results of the initial analysis and additional factors, suggesting the need for future large-scale studies to investigate this trend.

Assessing the clinical value of the Kruger strict morphology criteria over the World Health Organization fourth edition criteria.

OBJECTIVE: To assess if the newer Kruger strict morphology (WHO5; normal ≥4%) adds any clinical value beyond the criteria of the World Health Organization fourth edition (WHO4; normal ≥14%). DESIGN: Retrospective study. SETTING: Tertiary hospital. PATIENTS: Men without known azoospermia who had semen analysis (SA) collected over a 10-year period of time. INTERVENTIONS: Morphology classification under Kruger WHO5 strict criteria and WHO4 criteria. MAIN OUTCOME MEASURES: Correlation between the WHO5 and WHO4 morphological classifications. RESULTS: A total of 4,510 SAs were identified during the study period. Of these, both Kruger WHO5 and WHO4 morphologies were included in 932 SAs (20.7%) from a total of 691 men. The median age of the men was 37 years (interquartile range, 32.0-43.8 years). The mean (±SD) semen volume, sperm concentration, and motility were 2.6 ± 1.4 mL, 50.0 ± 35.6 × 106/mL, and 53.1% ± 18.6%, respectively. The correlation between the WHO4 and WHO5 morphology assessments was high (Spearman correlation coefficient = 0.94). Only 545 (58.5%) of 932 SAs had abnormal Kruger WHO5 morphology, of which 543 (99.6%) of 545 also had abnormal morphology by the WHO4 criteria. CONCLUSIONS: The Kruger WHO5 and WHO4 morphologic criteria correlate closely. Only two men (0.4%) with an abnormal Kruger morphology had normal WHO4 morphology. Given the limited predictive value of sperm morphology, the additional cost and effort of Kruger criteria may not be warranted in lieu of, or in addition to, the WHO4 classification.

Cigarette smoke affects posttranslational modifications and inhibits capacitation-induced changes in human sperm proteins.

Sperm are highly dependent on posttranslational modifications of proteins. Massive phosphorylation on tyrosine residue is required for sperm capacitation. Sumoylation has also been recently implicated in spermatogenesis and sperm functions. Cigarette smoke is known to cause oxidative stress in different tissues, and several studies suggest that it causes oxidative stress in sperm. Whether tobacco affects posttranslational modifications in human sperm is currently unknown. In this study, we show that a short exposure of human sperm to physiological concentrations of cigarette smoke extract (CSE) causes the partial de-sumoylation of many sperm proteins. Furthermore, the presence of a low concentration of CSE in the human tubal fluid during an induction of in vitro capacitation inhibits the capacitation-associated increase in protein phosphorylation. Collectively, changes in posttranslational modifications may be one of the mechanisms through which exposure to tobacco can negatively affect sperm functions and cause fertility problems.

Localization and identification of sumoylated proteins in human sperm: excessive sumoylation is a marker of defective spermatozoa.

BACKGROUND: Sumoylation is a type of post-translational modification that is implicated in the regulation of numerous cellular events. However, its role in the function of human sperm has not yet been characterized. METHODS AND RESULTS: In this study, both immunofluorescence and electron microscopy revealed that small ubiquitin-like modifiers (SUMO) SUMO1 and SUMO2/3 were highly enriched in the neck area of human sperm that is associated with the redundant nuclear envelope and were also detectable in the flagella and some head regions. Similar localization patterns of SUMO were also observed in mouse and fly sperm. Nonmotile, two-tailed, curled tailed, misshapen, microcephalic (small head) and aciphalic (no head) sperm exhibited abnormally high levels of sumoylation in their neck and tail regions relative to normal sperm. Numerous sumoylated proteins, ranging from 20 to 260 kDa, were detected via western blotting and identified by mass spectrometry, and 55 SUMO targets that were present specifically in human sperm, and not in the control fraction, corresponded to flagella proteins, proteins involved in the maturation and differentiation of sperm, heat shock proteins and important glycolytic and mitochondrial enzymes. The targets that were identified included proteins with specific functions in germ cells and sperm, such as heat shock-related 70-kDa protein 2, outer dense fiber protein 3, A-kinase anchor proteins 3 and 4, L-lactate dehydrogenase C, sperm protein associated with the nucleus on the X chromosome B/F, valosin-containing protein, seminogelins, histone H4 and ubiquitin. Coimmunoprecipitation experiments confirmed the sumoylation of semenogelin and indicated that some sperm proteins are modified by sumoylation and ubiquitination simultaneously. CONCLUSIONS: Numerous proteins are modified by sumoylation in human sperm; excessive sumoylation is a marker of defective spermatozoa.