Deletions within the male-specific region of the Y-chromosome, known as Y-Chromosome Microdeletions (YCMs), are present in as many as 5% and 10% of severe oligospermic and azoospermic men, respectively. These microdeletions are distinguished by which segment of the Y chromosome is absent, identified as AZFa (the most proximal segment), AZFb (middle), and AZFc (distal). The reported prevalence of YCMs within the world’s populations of infertile men displays vast heterogeneity, ranging from less than 2% to over 24% based on region and ethnicity. AZFc is the most commonly identified YCM, and its phenotypic presentation provides for the highest chance for fertility through artificial reproductive techniques. Conversely, deletions identified in the subregions of AZFa, AZFb, or any combination of regions containing these segments, are associated with low probabilities of achieving pregnancy. A putative mechanism explaining this discrepancy lies within the expression of autosomal, DAZ-like genes which could serve to “rescue” wild type AZFc gene expression and hence spermatogenesis. Nevertheless, recent reports challenge this dogma and stress the importance of further analysis when an AZFb deletion is detected. The screening thresholds to determine which oligospermic and azoospermic men are tested for potential YCMs has been recently contested. More recent literature supports lowering the threshold from 5 million sperm/mL of ejaculate to 1 million/mL as the frequency of YCMs in men with sperm concentrations between 1 and 5 million sperm/mL is very low (~0.8%). As such, subsequent guidelines should recommend a lower screening threshold. While YCMs are extremely common globally, the understanding of their clinical significance in the field remains scattered and without consensus. Furthermore, very little is currently known about partial deletions within the AZFc region, such as b1/b3, b2/b3, and gr/gr. Hence, this review aimed to summarize and discuss modern trends in the epidemiology, screening guidelines, and clinical considerations pertaining to YCMs.

Paternal environmental perturbations can influence the physiology and behavior of offspring. For example, our previous work showed reduced cocaine reinforcement in male, but not female, progeny of rat sires that self-administered cocaine. The information transfer from sire to progeny may occur through epigenetic marks in sperm, encompassing alterations in small noncoding RNAs, including microRNAs (miRNAs) and/or DNA methylation. Here, no reliable changes in miRNAs in the sperm of cocaine-relative to saline-experienced sires were identified. In contrast, 272 differentially methylated regions were observed in sperm between these groups. Two hypomethylated promoter regions in the sperm of cocaine-experienced rats were upstream of cyclin-dependent kinase inhibitor 1a (Cdkn1a). Cdkn1a mRNA also was selectively increased in the NAc of cocaine-sired male (but not female) offspring. Cocaine selfadministration also enhanced Cdkn1a expression in the accumbens of cocaine-sired rats. These results suggest that changes in Cdkn1a may play a role in the reduced cocaine reinforcing efficacy observed in cocaine-sired male rats. Introducing a 90 d delay between sire self-administration and breeding reversed both cocaine resistance and the increase in accumbens Cdkn1a mRNA in male offspring, indicating that cocaine-induced epigenetic modifications are eliminated with sperm turnover. Collectively, our results indicate that cocaine self-administration produces hypomethylation of Cdkn1a in sperm and a selective increase in the expression of this gene in the NAc of male offspring, which is associated with blunted cocaine reinforcement.

No abstract

Purpose:In order to accurately characterize how a history of radiation therapy affects the lifespan of replacement artificial urinary sphincters (AUSs), all possible sources of device failure must be considered. We assessed the competing risks of device failure based on radiation history in men with replacement AUSs.Materials and Methods:We identified men who had a replacement AUS in a single institutional, retrospective database. To assess survival from all-cause device failure based on radiation history and other factors, we conducted Kaplan-Meier, Cox proportional-hazards and competing risks analyses.Results:Among 247 men who had a first replacement AUS, men with a history of radiation had shorter time to all-cause device failure (median 1.4 vs 3.5 years for men with radiation vs without radiation history, p=0.02). On multivariable Cox-proportional hazards analysis, previous radiation was associated with increased risk of all-cause device failure (HR: 2.12, 95% CI: 1.30–3.43, p=0.002). On multivariable cause-specific hazards analysis, prior radiation was associated with a higher risk of erosion/infection (HR: 7.57, 95% CI: 2.27–25.2, p <0.001), but was not associated with risk of urethral atrophy (p=0.5) or mechanical failure (p=0.15).Conclusions:Among men with a replacement AUS, a history of pelvic radiation was associated with shorter time to device failure of any cause. Radiation was also specifically associated with a sevenfold increase in the risk of erosion or infection of replacement AUS, but not with urethral atrophy or mechanical failure. Patients with a replacement AUS should be appropriately counseled on how radiation history may impact outcomes of future revisions.