No abstract

Traditionally, testosterone and estrogen have been considered to be male and female sex hormones, respectively. However, estradiol, the predominant form of estrogen, also plays a critical role in male sexual function. Estradiol in men is essential for modulating libido, erectile function, and spermatogenesis. Estrogen receptors, as well as aromatase, the enzyme that converts testosterone to estrogen, are abundant in brain, penis, and testis, organs important for sexual function. In the brain, estradiol synthesis is increased in areas related to sexual arousal. In addition, in the penis, estrogen receptors are found throughout the corpus cavernosum with high concentration around neurovascular bundles. Low testosterone and elevated estrogen increase the incidence of erectile dysfunction independently of one another. In the testes, spermatogenesis is modulated at every level by estrogen, starting with the hypothalamus-pituitary-gonadal axis, followed by the Leydig, Sertoli, and germ cells, and finishing with the ductal epithelium, epididymis, and mature sperm. Regulation of testicular cells by estradiol shows both an inhibitory and a stimulatory influence, indicating an intricate symphony of dose-dependent and temporally sensitive modulation. Our goal in this review is to elucidate the overall contribution of estradiol to male sexual function by looking at the hormone's effects on erectile function, spermatogenesis, and libido.

Azoospermia in men requires microsurgical reconstruction or a procedure for sperm retrieval with assisted reproduction to allow fertility. While the chance of successful retrieval of sperm in men with obstructive azoospermia approaches >90%, the chances of sperm retrieval in men with non-obstructive azoospermia (NOA) are not as high. Conventional procedures such as fine needle aspiration of the testis, testicular biopsy and testicular sperm extraction are successful in 20–45% of men with NOA. With microdissection testicular sperm extraction (micro-TESE), the chance of successful retrieval can be up to 60%. Despite this increased success, the ability to counsel patients preoperatively on their probability of successful sperm retrieval has remained challenging. A combination of variables such as age, serum FSH and inhibin B levels, testicular size, genetic analysis, history of Klinefelter syndrome, history of cryptorchidism or varicocele and histopathology on diagnostic biopsy have provided some insight into the chance of successful sperm retrieval in men with NOA. The goal of this review was to evaluate the preoperative factors that are currently available to predict the outcome for success with micro-TESE.

Sperm were successfully identified in up to one half of the men with MA after micro-TESE. Among men with MA, late MA seems to be the best predictor of successful sperm retrieval with micro-TESE.

Vasectomy is the most common urological procedure in the United States with 18% of men having a vasectomy before age 45. A significant proportion of vasectomized men ultimately request vasectomy reversal, usually due to divorce and/or remarriage. Vasectomy reversal is a commonly practiced but technically demanding microsurgical procedure that restores patency of the male excurrent ductal system in 80–99.5% of cases and enables unassisted pregnancy in 40–80% of couples. The discrepancy between the anastomotic patency rates and clinical pregnancy rates following vasectomy reversal suggests that some of the biological consequences of vasectomy may not be entirely reversible in all men. Herein we review what is known about the biological sequelae of vasectomy and vasectomy reversal in humans, and provide a succinct overview of the evaluation and surgical management of men desiring vasectomy reversal.

Testosterone replacement therapy (TRT) is a widely used treatment for men with symptomatic hypogonadism. The benefits seen with TRT, such as increased libido and energy level, beneficial effects on bone density, strength and muscle as well as cardioprotective effects, have been well-documented. TRT is contraindicated in men with untreated prostate and breast cancer. Men on TRT should be monitored for side-effects such as polycythemia, peripheral edema, cardiac and hepatic dysfunction.

Microsurgical epididymal sperm aspiration (MESA) refers to retrieval of sperm-containing fluid from optimal areas of the epididymis that are selected and sampled using high-power optical magnification provided by an operating microscope. Retrieved sperm are subsequently used for intracytoplasmic sperm injection (ICSI) to induce fertilization and pregnancy. MESA is considered by many experts to be the gold standard technique for sperm retrieval in men with obstructive azoospermia given its high yield of quality sperm, excellent reported fertilization and pregnancy rates, and low risk of complications. However, MESA must be performed in an operating room, requires microsurgical skills and is only useful for reproduction using ICSI. Herein we present an overview of the evaluation of candidate patients for MESA, the technical performance of the procedure and the outcomes that have been reported.

Cite as: Can Urol Assoc J 2015;9(1-2):65-8. http://dx