Renoprotective effects of laxative linaclotide: Inhibition of acute kidney injury and fibrosis in a rat model of renal ischemia-reperfusion.

Ischemia-reperfusion (I/R) leads to tissue damage in transplanted kidneys, resulting in acute kidney injury (AKI) and chronic graft dysfunction, which critically compromises transplant outcomes, such as graft loss. Linaclotide, a guanylate cyclase C agonist clinically approved as a laxative, has recently been identified to exhibit renoprotective effects in a chronic kidney disease (CKD) model. This study evaluates the therapeutic effects of linaclotide on AKI triggered by I/R in a rat model with an initial comparison with other laxatives. Here, we show that linaclotide administration resulted in substantial reduction in serum creatinine levels, reflective of enhanced renal function. Histological examination revealed diminished tubular damage, and Sirius Red staining confirmed less collagen deposition, collectively indicating preserved structural integrity and mitigation of fibrosis. Further analysis demonstrated lowered expression of TGF-ß and associated fibrotic markers, α-SMA, MMP2, and TIMP1, implicating the downregulation of the fibrogenic TGF-ß pathway by linaclotide. Furthermore, one day after I/R insult, linaclotide profoundly diminished macrophage infiltration and suppressed critical pro-inflammatory cytokines such as TNF, IL-1ß, and IL-6, signifying its potential to disrupt initial inflammatory mechanisms integral to AKI pathology. These findings suggest that linaclotide, with its established safety profile, could extend its benefits beyond gastrointestinal issues and potentially serve as a therapeutic intervention for organ transplantation. Additionally, it could provide immediate and practical insights into selecting laxatives for managing patients with AKI or CKD, regardless of the cause, and for those receiving dialysis or transplant therapy.

Role of varicocele repair in the era of assisted reproductive technologies: Lessons from 2000 cases of microsurgical varicocele repair.

Backgrounds: In an era of advanced maternal age, there is less conclusive evidence regarding the treatment outcomes of varicocele repair for assisted reproductive technology (ART). Progress in basic research on varicocele is notable whereas there are many clinically relevant points to discuss. Methods: Based on our experience with more than 2000 cases of microsurgical varicocele repair, we focused on the effectiveness of varicocele repair, pathophysiology, surgical approaches, contributions to ART, sperm DNA fragmentation, and varicocele-associated azoospermia in this review with the aim of identifying clearer directions for basic and clinical research on varicocele. Results: Microsurgical low ligation for varicocele repair is expected to remain the gold standard for surgical therapy. Based on the findings from a number of systematic reviews and meta-analyses, negative opinions regarding the efficacy of microsurgical varicocele repair in male infertility treatment have become virtually nonexistent. However, the majority of evidence regarding surgical indications and effectiveness pertains to improvements in semen parameters or non-ART pregnancy rates. Conclusions: Further understandings regarding to pathophysiology of varicocele will likely be gained through comprehensive genetic, transcriptomic, and epigenetic analyses using blood and testicular samples from humans and we hope to develop new diagnostic methods and pharmacotherapy.

Evaluation of sexual function after robot-assisted radical prostatectomy: A farewell to IIEF questionnaire.

Longevity with localized prostate cancer (PCa) has been achieved, and the contribution of robot-assisted radical prostatectomy (RARP) to cancer control is evident. The next step to investigate in the treatment of localized PCa is improvement of the quality of life (QOL) after RARP. Erectile dysfunction has been considered a major surgical complication, and patient satisfaction after RARP has not improved despite the development of nerve preservation and penile rehabilitation. To comprehensively understand sexual dysfunction after RARP, we must investigate other complications with regard to sexual health, including low sexual desire, disturbed orgasmic function (i.e., anejaculation, orgasm intensity, painful orgasm, and climacturia), shortening of penile length, penile curvature (Peyronie's disease) and unique psychological alterations after the diagnosis of PCa, which are neglected side effects after prostatectomy. In this context, routine evaluation of erectile function by the International Index of Erectile Function only is not sufficient to understand patients' difficulties. A questionnaire is just one way of enabling patients to evaluate their pre- and postoperative concerns; listening to patients face-to-face is warranted to detect symptoms. Understanding the relationship between symptoms and preserved nerve localization can ultimately provide an individualized nerve-sparing procedure and improve patient satisfaction after RARP. In combination with psychological counseling, including the partner and medical treatment, such as testosterone replacement, it is time to reconsider ways to improve sexual dysfunction after RARP.

Prominin-1 deletion results in spermatogenic impairment, sperm morphological defects, and infertility in mice.

Purpose: Spermatogenesis is a complex process orchestrated by several essential genes. Prominin-1 (Prom1/PROM1) is a gene that is expressed in the testis but with a poorly understood role in spermatogenesis. Methods: We used Prom1 knockout (Prom1 KO) mice to assess the role of Prom1 in spermatogenesis. To this end, we performed immunohistochemistry, immunofluorescence, western blotting, ß-galactosidase staining, and apoptosis assay. Additionally, we analyzed the morphology of sperm and assessed litter sizes. Results: We observed that PROM1 is localized to the dividing spermatocytes in seminiferous epithelial cells, sperm, and columnar epithelium in the epididymis. In the Prom1 KO testis, an aberrant increase in apoptotic cells and a decrease in proliferating seminiferous epithelial cells were observed. Cellular FLICE-like inhibitory protein (c-FLIP) and extracellular signal-regulated kinase 1/2 (ERK1/2) expression were also significantly decreased in Prom1 KO testis. In addition, a significantly increased number of epididymal spermatozoa with abnormal morphology and less motility was found in Prom1 KO mice. Conclusions: PROM1 maintains spermatogenic cell proliferation and survival via c-FLIP expression in the testis. It is also involved in sperm motility and fertilization potential. The mechanism underlying the effect of Prom1 on sperm morphology and motility remains to be identified.

Testicular localization of activating transcription factor 1 and its potential function during spermatogenesis†.

Activating transcription factor 1 (ATF1), belonging to the CREB/ATF family of transcription factors, is highly expressed in the testes. However, its role in spermatogenesis has not yet been established. Here, we aimed to elucidate the impact of ATF1 in spermatogenesis by examining the expression pattern of ATF1 in mice and the effect of ATF1 knockdown in the mouse testes. We found that ATF1 is expressed in various organs, with very high levels in the testes. Immunohistochemical staining showed that ATF1 was localized in the nuclei of spermatogonia and co-localized with proliferating cell nuclear antigen. In ATF1-deficient mice, the seminiferous tubules of the testis contained cells at all developmental stages; however, the number of spermatocytes was decreased. Proliferating cell nuclear antigen expression was decreased and apoptotic cells were rare in the seminiferous tubules. These results indicate that ATF1 plays a role in male germ cell proliferation and sperm production.

Testicular Temperature and the Effects of Orchiopexy in Infants with Cryptorchidism.

PURPOSE: Testicular temperature should remain low to maintain optimal function of germ cells; however, information regarding testicular temperature in infants and the effect of cryptorchidism and its correction, including laparoscopic staged Fowler-Stephens orchiopexy (LSFSO), is limited. MATERIALS AND METHODS: A total of 82 infants with unilateral palpable cryptorchidism, 24 with nonpalpable testes who underwent unilateral LSFSO and 20 with scrotal hydrocele were included. Ultrasonographic determination of testicular volume and measurement of testicular temperature but not scrotal surface temperature using a Coretemp CTM204® (Terumo, Tokyo) were performed before and 12 months after orchiopexy. The effects of the route of testicular delivery, conventionally through a new hiatus medial to the inferior epigastric vessels or through the transinguinal approach, were investigated in the LSFSO cases. RESULTS: Undescended testicular volume was significantly increased after orchiopexy (0.80 ml to 0.92 ml, p <0.0001). The preoperative testicular temperature (35.1C) was significantly higher than that of the control (34.4C, p <0.0001), and significant decreases in testicular temperature occurred after orchiopexy (34.3C, p <0.0001). A multivariate analysis showed that a decrease in testicular temperature was a factor associated with postoperative testicular development. Twelve months after LSFSO, transinguinal approach was shown to be more effective in decreasing the testicular temperature than the conventional approach (34.4 and 35.3C, respectively, p <0.05). CONCLUSIONS: Orchiopexy is effective in correcting the high-temperature environment caused by cryptorchidism. In the case of nonpalpable testes treated by LSFSO, transinguinal fixation is more effective than the conventional approach in reducing testicular temperature, but a longer followup period is necessary to draw a final conclusion.

Patient-reported outcomes and biochemical alterations during hormonal therapy in men with hypogonadotropic hypogonadism who have finished infertility treatment.

Male hypogonadotropic hypogonadism (MHH) is effectively treated by gonadotropins with a high rate of ejaculate sperm and paternity; however, there is no information regarding the appropriate management, including patient-reported outcomes (PROs), of men with MHH who have finished infertility treatment. To compare health-related quality of life, erectile function and biochemical alterations in men with MHH who were treated with testosterone replacement therapy (TRT) or human chorionic gonadotropin (hCG). Twenty-six MHH patients (mean age: 34 years) who needed to improve their androgen deficiency symptoms underwent either hCG therapy (n = 16, started with self-injection of 2,000-7,500 IU per week) or TRT (n = 10, testosterone enanthate 250 mg every 3 weeks). The 36-item Short Form Health Survey (SF-36) questionnaire, five-item International Index of Erectile Function (IIEF-5) and hormonal and biochemical analyses were assessed every 3 months. Changes and comparison of each treatment regarding these parameters were analyzed. Both hCG and TRT significantly improved all domains of the SF-36, except for bodily pain and social functioning. hCG significantly improved the general and mental health domains compared with TRT. Significant improvements in IIEF-5 were observed with both treatments, showing significant improvement with hCG compared to TRT. TRT caused progressive testicular atrophy. There were significant decreases in waist circumference and triglycerides in both treatment groups and significant elevations in prostate-specific antigen and hematocrit. Both hCG and TRT are effective and safe, with preferable PROs by hCG, for treating androgen deficiency in men with MHH who do not need infertility treatment.

Genome medicine in male infertility: From karyotyping to single-cell analysis.

Male infertility is a multifactorial pathological condition that affects half of infertile couples. The majority of cases are categorized as idiopathic, especially in cases of nonobstructive azoospermia (NOA). An increasing number of genetic abnormalities have been shown to cause spermatogenic impairment with the development of microarray technologies and next-generation sequencing (NGS), moving beyond classical karyotype and polymerase chain reaction analyses of targeted genes. However, the majority of gene mutations, such as Klinefelter syndrome, azoospermia factor microdeletion, or congenital bilateral absence of the vas deferens, fail to function in a one gene-one phenotype manner. Single-cell transcriptome analysis performed using human testicular samples has begun to be published, which has brought about a more comprehensive understanding of testicular pathology. NGS also enables omics approaches, which provide more powerful tools to interrogate the genome, epigenome, transcriptome, and proteome. Simultaneously, the involvement of environmental factors and comorbidities, which may potentially regulate epigenetic factors, has been shown, resulting in a more complex understanding of the pathophysiology of spermatic disorders, especially NOA. The combination of phenotypic data and large amounts of bioinformatical data obtained by NGS may provide a more comprehensive understanding of the pathophysiology of male infertility, which will contribute not only to a diagnosis but also to the proper selection of infertility treatment and the development of new treatment modalities for male infertility.

Transcriptome Analysis to Identify Human Spermatogonial Cells from Sertoli Cell-Only Testes.

PURPOSE: We sought to determine whether gene products from spermatogenic cells could be detected in Sertoli cell-only testes. Transcriptome analysis using next generation sequencing was performed using human testicular samples. MATERIALS AND METHODS: This study enrolled 20 men with nonobstructive azoospermia with a histological diagnosis of Sertoli cell-only and no germ cells on in vitro fertilization analysis and 5 with obstructive azoospermia and histologically normal spermatogenesis. Individual differences in the transcriptome of obstructive azoospermia testicular tissues generated on the Illumina® platform were compared as the number of fragments per kilobase of exon per million mapped sequence reads. We confirmed mRNA expression and targeted gene product localization by quantitative reverse transcriptase-polymerase chain reaction and immunohistochemical analysis, respectively. RESULTS: Using next generation sequencing we analyzed 5,666 of the 23,003 screened genes. As representative markers of immature germ cells, UTF1, CD9, DDX4, EPCAM, GFRA1, KIT, LIN28, DMRT, GPR125, UCHL1 and NANOG transcripts were detected in 13 Sertoli cell-only samples (65%). Reverse transcriptase-polymerase chain reaction showed significant mRNA expression of UTF1, CD9, DDX4 and KIT in Sertoli cell-only samples. Immunostaining revealed the localization of DDX4-positive cells, presumably spermatogonia, in 9 Sertoli cell-only samples (45%). These cells lacked proliferative cell nuclear antigen expression. CONCLUSIONS: A number of Sertoli cell-only testes contain immature germ cells (spermatogonia and spermatogenic stem cells) with various gene expression profiles. Sertoli cell-only is a heterogeneous pathophysiology which may be corrected by medical treatment or regenerative technologies.

Bulk Alignment of Chromonic Aggregates During Swelling of Hydrogels.

This study demonstrates that the bulk alignment of chromonic aggregates can be achieved during the swelling of hydrogels. Swelling of an ionic hydrogel immersed in an aqueous solution of disodium cromoglycate reorients the chromonic aggregates, and millimeter-thick optically anisotropic hydrogels are obtained. These anisotropic hydrogels contain the chromonic aggregates at a condensed concentration as high as in the columnar phase of a normal chromonic aqueous solution, although the X-ray diffraction results show much less stacking order and orientational order of the aggregates. Furthermore, anisotropic mechanical properties of the hydrogels are observed due to the anisotropic alignment of the chromonic aggregates.

Outcomes of partial intussusception and endo-to-side vasoepididymostomy in men with epididymal obstructive azoospermia.

OBJECTIVES: Vasoepididymostomy is an ideal surgical approach for epididymal obstructive azoospermia. The aim of the present study was to compare reproductive outcomes of vasoepididymostomy with several anastomotic techniques, including end-to-side and longitudinal intussusception vasoepididymostomy, and partial intussusception and endo-to-side vasoepididymostomy. METHODS: A case-control study including 110 infertile men with epididymal obstructive azoospermia with mean age of 35 years was carried out. Univariate and multivariate analyses using clinical factors were carried out to predict patency and non-assisted reproductive technology pregnancy. Johnsen score count and proliferating cell nuclear antigen expression were used as surrogates for spermatogenic function. Operative time, number of 10-0 sutures and late failure rates were also compared. RESULTS: The overall patency and non-assisted reproductive technology pregnancy rates were 70% and 32%, respectively. Multivariate analyses showed that the presence of motile sperm in the epididymis and a higher spermatogenic function (P < 0.05) were independent predictors for patency, and that a higher spermatogenic function and anastomosis at the caput/corpus (P < 0.001) were predictors for non-assisted reproductive technology pregnancy. The operative time was significantly shorter with partial intussusception and endo-to-side than with the other techniques (P < 0.001), and the number of 10-0 sutures was significantly less with partial intussusception and endo-to-side than with longitudinal intussusception vasoepididymostomy (P < 0.01). CONCLUSIONS: Partial intussusception and endo-to-side as well as end-to-side and longitudinal intussusception vasoepididymostomy are feasible vasoepididymostomy techniques for epididymal obstruction. Spermatogenic function plays important roles in patency and non-assisted reproductive technology pregnancy after vasoepididymostomy. Depending on the surgeon's expertise, partial intussusception and endo-to-side provides similar functional outcomes to those of more established vasoepididymostomy techniques, such as end-to-side and longitudinal intussusception vasoepididymostomy, and it could therefore be considered an effective technique for seminal reconstruction in patients with epididymal obstructive azoospermia.

Clinical Practice Guidelines for Bladder Cancer 2019 edition by the Japanese Urological Association: Revision working position paper.

The Clinical Practice Guidelines for Bladder Cancer edited by the Japanese Urological Association were first published in 2009 and a revised edition was released in 2015. Four years has passed since the 2015 edition, and the clinical practice environment surrounding bladder cancer has drastically changed during that time. The main changes include: (i) insurance coverage of a new diagnostic method for non-muscle-invasive bladder cancer; (ii) insurance coverage of an immune checkpoint inhibitor in advanced and metastatic bladder cancer; and (iii) advances in robot-assisted radical cystectomy as a minimally invasive treatment for muscle-invasive bladder cancer. A paradigm shift in bladder cancer diagnosis and treatment is occurring day by day. Therefore, in this 2019 edition, while dealing with the above changes, we carefully selected clinical questions with clear evidence and included other clinically important points in the general statement. We also added a new chapter on rare cancers of the urinary tract. As a new method for the evaluation of study evidence level, we introduce "The Grading of Recommendations Assessment, Development and Evaluation" system modified to Japanese by the Medical Information Network Distribution Service.

Clinical Practice Guidelines for Bladder Cancer 2019 update by the Japanese Urological Association: Summary of the revision.

OBJECTIVES: Despite just a 4-year interval from the last version (2015) of the Clinical Practice Guidelines for Bladder Cancer, several dramatic paradigm shifts have occurred in the latest clinical practice regarding both the diagnosis and treatment of bladder cancer. Herein, we updated the 2019 version of the Clinical Practice Guidelines for Bladder Cancer under the instruction of the Japanese Urological Association. METHODS: We previously reported in a revision working position paper for Clinical Practice Guidelines for Bladder Cancer 2019 edition and described the methods of revision detail. RESULTS: The major points of change in the 2019 version are presented and explanations are given as follows: (i) introduction of the new reference assessment system; (ii) modification of the risk classification for non-muscle-invasive bladder cancer; (iii) addition of clinical questions for the new tumor-visible techniques in non-muscle-invasive bladder cancer; (iv) inclusion of minimally invasive surgeries for muscle-invasive bladder cancer and immune checkpoint inhibitors for locally advanced/metastatic muscle-invasive bladder cancer; (v) overview chapter of the histological variant of urothelial cancer and rare cancers of the bladder; and (vi) recommendation of follow up in non-muscle-invasive bladder cancer and muscle-invasive bladder cancer. CONCLUSIONS: Guidelines should be updated based on the current evidence and updates carried out without delay. The hope is that this guidelines will be assessed by many urologists and will be the cornerstone for the next revision.

Transperitoneal versus retroperitoneal laparoscopic adrenalectomy for large pheochromocytoma: Comparative outcomes.

OBJECTIVES: To evaluate operative and oncological outcomes of laparoscopic adrenalectomy through a transperitoneal approach and retroperitoneal approach for large (>5 cm in diameter) pheochromocytomas. METHODS: We retrospectively compared the results of a transperitoneal approach with those of a retroperitoneal approach in 22 patients (mean age 57.5 years, range 38-76 years) with unilateral large pheochromocytomas (12 right, 10 left). The mean body mass index, operation time, pneumoperitoneum time, estimated blood loss, fluctuation in blood pressure and complication rate were compared between the two approaches. RESULTS: The mean tumor diameter (range) was 7.0 cm (range 5.2-15.5 cm), and no significant differences were observed between the transperitoneal approach and retroperitoneal approach in any baseline clinical parameter. For right-sided procedures, significant differences were found for operation time (113 vs 85 min), pneumoperitoneum time (93 vs 64 min) and estimated blood loss (96 vs 23 mL; P < 0.05, transperitoneal approach and retroperitoneal approach, respectively). No open conversion or recurrence was reported, but one right transperitoneal approach case required blood transfusion. No difference in these parameters was noted on the left side. CONCLUSIONS: For right side procedures, the retroperitoneal approach is feasible, safer and faster than the transperitoneal approach for large pheochromocytomas. Early transection of the feeding artery is beneficial for managing the tumor and reducing the risk of bleeding.

Klinefelter syndrome: From pediatrics to geriatrics.

BACKGROUND: Klinefelter syndrome (KS) is one of the major causes of nonobstructive azoospermia (NOA). Microdissection testicular sperm extraction (micro-TESE) is often performed to retrieve sperm. Infertility specialists have to care for KS patients on a lifelong basis. METHODS: Based on a literature review and our own experience, male infertility treatment and KS pathophysiology were considered on a lifelong basis. MAIN FINDINGS: Patients diagnosed early often have an increased number of aberrant X chromosomes. Cryptorchidism and hypospadias are often found, and surgical correction is required. Cryopreservation of testicular sperm during adolescence is an issue of debate because the sperm retrieval rate (SRR) in KS patients decreases with age. The SRR in adult KS patients is higher than that in other patients with NOA; however, low testosterone levels after micro-TESE will lower the general health and quality of life. KS men face a number of comorbidities, such as malignancies, metabolic syndrome, diabetes, cardiovascular disease, bone disease, and immune diseases, which ultimately results in increased mortality rates. CONCLUSION: A deeper understanding of the pathophysiology of KS and the histories of KS patients before they seek infertility treatment, during which discussions with multidisciplinary teams are sometimes needed, will help to properly treat these patients.

Nationwide survey of urological specialists regarding male infertility: results from a 2015 questionnaire in Japan.

Purpose: To investigate the incidence, etiology, treatment indications, and outcomes regarding infertile male patients in Japan. Methods: Between April, 2014 and March, 2015, the authors contacted 47 clinical specialists in male infertility who had been certified by the Japan Society for Reproductive Medicine. The participating clinicians were sent a questionnaire regarding information on their infertile patients, according to etiology and the number and success rates of male infertility operations that had been performed in their practice. Results: Thirty-nine specialists returned the questionnaire and provided information regarding 7268 patients. The etiology of infertility included testicular factors, sexual disorders, and seminal tract obstruction. During the study year, the clinicians performed varicocelectomies, testicular sperm extractions (TESEs), and re-anastomoses of the seminal tract. The rate of successful varicocelectomies was >70%. The sperm retrieval rates with conventional TESE and microdissection TESE were 98.3% and 34.0%, respectively, while the patency rates with vasovasostomy and epididymovasostomy were 81.8% and 61.0%, respectively. Conclusion: Surgical outcomes for infertile male patients are favorable and can be of great clinical benefit for infertile couples. To achieve this, urologists should work in collaboration with gynecological specialists in order to optimize the treatment of both partners.

Predictive Factors for Sperm Recovery after Varicocelectomy in Men with Nonobstructive Azoospermia.

PURPOSE: The ability of testicular histopathology to predict the success of microsurgical varicocelectomy in patients with nonobstructive azoospermia was investigated. We used a next generation sequencer to compare the transcriptomes of varicocelectomy responsive and nonresponsive testes to identify the factors that predict sperm in the ejaculate. MATERIALS AND METHODS: A total of 83 men with nonobstructive azoospermia and left varicocele underwent microsurgical varicocelectomy with simultaneous testicular biopsy. Transcriptome results using the Illumina® platform were expressed as the number of fragments per kb. Immunohistochemistry for proliferating cell nuclear antigen was performed on tissue samples from men with maturation arrest. Sperm recovery was evaluated with respect to patient age, testicular volume, varicocele grade, follicle-stimulating hormone level and testicular histology. RESULTS: Mean age was 34 years and the mean follicle-stimulating hormone level was 12.3 IU/l. Sperm recovery was confirmed in 20 patients (24%) within 12 months after varicocelectomy, including 1 of 43 (2%) with Sertoli cell only, 10 of 27 (37%) with maturation arrest and 9 of 13 (69%) with hypospermatogenesis. Comparisons of 23,003 genes between the groups with and without sperm in the ejaculate of men with maturation arrest revealed a number of cell cycle related genes that were up-regulated and several antioxidant genes that were down-regulated in men with sperm recovery. Proliferating cell nuclear antigen expression was significantly higher in the 10 varicocelectomy responsive men than in the 17 nonresponsive men. CONCLUSIONS: Transcriptome analysis of patients with maturation arrest revealed a distinct difference in the transcription of cell cycle regulation genes between varicocelectomy responsive and nonresponsive patients. Cell cycle assessment can predict sperm recovery and could improve our understanding of varicocele pathophysiology.

Gonadotoropin actions on spermatogenesis and hormonal therapies for spermatogenic disorders [Review].

Microdissection testicular sperm extraction and intracytoplasmic sperm injection have made it possible for men with non-obstructive azoospermia (NOA) to conceive a child. A majority of men cannot produce sperm because spermatogenesis per se is believed to be "irreversibly" disturbed. For these men, it has been thought that any hormonal therapy will be ineffective. Further understandings of endocrinological regulation of spermatogenesis are needed and LH or FSH receptor knock out (KO) mice have revealed the roles of gonadotropin separately. Spermatogenesis has been shown to shift during evolution from FSH to LH dominance because LH receptor KO causes infertility while FSH receptor KO does not. High concentrations of intratesticular testosterone secreted from Leydig cells, ranging from 100- to 1,000-fold higher than in the systemic circulation, has pivotal roles during spermatogenesis. This is especially important during spermiogenesis, a post-meiotic step for progression from round to elongating spermatids. Sertoli cells are the target of FSH and have numerous androgen receptors, indicating that Sertoli cells are regulated by FSH and the paracrine functions of testosterone. In combination with Leydig cell-derived growth factors, particularly epidermal growth factor-like growth factors, Sertoli cells support spermatogenesis, especially at proximal levels of spermatogenesis (e.g., spermatogonial proliferation). Taken together, the current knowledge from human studies indicating that testosterone optimization by clomiphene, hCG and/or aromatase inhibitors and high dose hCG/FSH treatment can, at least in part, improve spermatogenesis in NOA. Accordingly hormonal therapy may open a therapeutic window for sperm production in selected patients.