The effect of sirolimus on sex hormone levels of male renal transplant recipients

Thyroid, Gonadal and Adrenal Dysfunction in Kidney Transplant Recipients: A Review for the Clinician

While chronic kidney disease-associated mineral and bone disorders (CKD-MBD) prevail in the endocrinological assessment of CKD patients, other endocrine abnormalities are usually overlooked. CKD is associated with significant thyroid, adrenal and gonadal dysfunction, while persistent and de novo endocrinological abnormalities are frequent among kidney transplant recipients (KTR). Low T3 levels prior to transplantation may help identify those at risk for delayed graft function and are often found in KTR. Thyroid surveillance after kidney transplantation should be considered due to structural anomalies that may occur. Despite the rapid recovery of gonadal hormonal secretion after renal transplantation, fertility is not completely restored. Testosterone may improve anemia and general symptoms in KTR with persistent hypogonadism. Female KTR may still experience abnormal uterine bleeding, for which estroprogestative administration may be beneficial. Glucocorticoid administration suppresses the hypothalamic-pituitary-adrenal axis in KTR, leading to metabolic syndrome. Patients should be informed about signs and symptoms of hypoadrenalism that may occur after glucocorticoid withdrawal, prompting adrenal function assessment. Clinicians should be more aware of the endocrine abnormalities experienced by their KTR patients, as these may significantly impact the quality of life. In clinical practice, awareness of the specific endocrine dysfunctions experienced by KTR patients ensures the correct management of these complications in a multidisciplinary team, while avoiding unnecessary treatment.

Effect of Neuroendocrine Neoplasm Treatment on Human Reproductive Health and Sexual Function

Neuroendocrine neoplasms (NEN) are characterized by a wide clinical heterogeneity and biological variability, with slow progression and long survival in most cases. Although these tumors can affect young adults, there are few studies that focus on the sexual and reproductive system. The aim of this review was to evaluate the effect of NEN treatment, including somatostatin analogues (SSA), targeted therapy (Everolimus and Sunitinib), radiolabeled-SSA and chemotherapy, on male and female reproductive systems and sexual function. This narrative review was performed for all available prospective and retrospective studies, case reports and review articles published up to March 2022 in PubMed. To date, few data are available on the impact of SSA on human fertility and most of studies come from acromegalic patients. However, SSAs seem to cross the blood–placental barrier; therefore, pregnancy planning is strongly recommended. Furthermore, the effect of targeted therapy on reproductive function is still undefined. Conversely, chemotherapy has a well-known negative impact on male and female fertility. The effect of temozolomide on reproductive function is still undefined, even if changes in semen parameters after the treatment have been described. Finally, very few data are available on the sexual function of NEN treatment.

Sexual Dysfunction Among Patients With Chronic Kidney Disease

Sexual dysfunction (SD) in patients with chronic kidney disease is common and negatively impacts quality of life. SD is often under-appreciated because of overall low awareness. Diagnosis of SD is subjective, and manifestations can be different among men and women. Causes of SD are multifactorial, including psychological disorders, hormonal imbalances, vascular disorders, neurological disorders, and medication side effects. Non-specific approaches to improving sexual function include addressing underlying psychological disorders, promoting lifestyle modifications, optimizing dialysis care, and facilitating successful kidney transplantation, whereas treatment with phosphodiesterase type 5 inhibitor, hormone replacement, and mechanical devices can be offered to patients with specific indications.

The effect of paternal exposure to immunosuppressive drugs on sexual function, reproductive hormones, fertility, pregnancy and offspring outcomes: a systematic review

BACKGROUND

Information regarding the possible influence of immunosuppressive drugs on male sexual function and reproductive outcomes is scarce. Men diagnosed with immune-mediated diseases and a wish to become a father represent an important neglected population since they lack vital information to make balanced decisions about their treatment.

OBJECTIVE AND RATIONALE

The aim of this research was to systematically review the literature for the influence of paternal immunosuppressive drug use on many aspects of male sexual health, such as sexual function, fertility, pregnancy outcomes and offspring health outcomes.

SEARCH METHODS

A systematic literature search was performed in the bibliographic databases: Embase (via Elsevier embase.com), MEDLINE ALL via Ovid, Cochrane Central Register of Trials (via Wiley) and Web of Science Core Collection. Additionally, Google Scholar and the Clinical trial registries of Europe and the USA were searched. The databases were searched from inception until 31 August 2019. The searches combined keywords regarding male sexual function and fertility, pregnancy outcomes and offspring health with a list of immunosuppressive drugs. Studies were included if they were published in English and if they included original data on male human exposure to immunosuppressive drugs. A meta-analysis was not possible to perform due to the heterogeneity of the data.

OUTCOMES

A total of 5867 references were identified, amongst which we identified 161 articles fulfilling the eligibility criteria. Amongst these articles, 50 included pregnancy and offspring outcomes and 130 included sexual health outcomes. Except for large Scandinavian cohorts, most of the identified articles included a small number of participants. While a clear negative effect on sperm quality was evident for sulfasalazine and cyclophosphamide, a dubious effect was identified for colchicine, methotrexate and sirolimus. In three articles, exposure to tumour necrosis factor-α inhibitors in patients diagnosed with ankylosing spondylitis resulted in improved sperm quality. The information regarding pregnancy and offspring outcomes was scant but no large negative effect associated with paternal immunosuppressive drug exposure was reported.

WIDER IMPLICATIONS

Evidence regarding the safety of immunosuppressive drugs in men with a wish to become a father is inconclusive. The lack of standardisation on how to evaluate and report male sexual function, fertility and reproduction as study outcomes in men exposed to immunosuppressive drugs is an important contributor to this result. Future research on this topic is needed and should be preferably done using standardised methods.

Hormonal (Im)Balance and Reproductive System’s Disorders in Transplant Recipients—A Review

Simple Summary

Nowadays, the average human life expectancy is increasing. This applies to both healthy and chronically ill people. It is possible due to improvements in technology, living conditions, and better, more accessible medical care. As the number of patients with end-stage organ failure increases and due to great progress in modern transplantology, every year the number of transplantations rises worldwide. Organ transplantation is not only an ultimate form of therapy but also, especially nowadays, a life-saving procedure. Patients who have undergone transplantation need to face the problem of long-term immunosuppressive therapy on a daily basis, which prolongs the proper function of the grafted organ and prevents the development of graft-versus-host disease. On the other hand, numerous side effects are associated with the usage of these medicaments, among these are disturbances in sex-related hormones, therefore influencing fertility.

Abstract

The rising need for treatment of end stage of organ failure results in an increased number of graft recipients yearly. The most commonly transplanted organs are kidney, heart, liver, bone marrow, lung and skin. The procedure of transplantation saves and prolongs the lives of chronically ill patients or at least improves the quality. However, following transplantation recipients must take immunosuppressive drugs on a daily basis. Usually, the immunosuppressive therapy comprises two or three drugs from different groups, as the mechanism of their action varies. Although the benefits of intake of immunosuppressants is undeniable, numerous side effects are associated with them. To different extents, they are neurotoxic, nephrotoxic and may influence the function of the reproductive system. Nowadays, when infertility is an urgent problem even among healthy pairs, transplant recipients face the problem of disturbance in the hypothalamic−pituitary axis. This review will provide an overview of the most common disturbances among the concentration of sex-related hormones in recipients of both sexes at different ages, including sexually immature children, adults of reproductive age as well as elderly women and men. We have also focused on the numerous side effects of immunosuppressive therapy regarding function and morphology of reproductive organs both in males and females. The current review also presents the regimen of immunosuppressive therapy and time since transplantation.

Impact of antiangiogenic treatment on the erectile function in patients with advanced renal cell carcinoma

We longitudinally assessed erectile function as well as the willingness to use pro-erectile treatment in a cohort on AAT for advanced RCC. Thirty-seven patients with advanced RCC completed the five-item version of the International Index of Erectile Function (IIEF-5) and other interview items before (T0) and 12 weeks into therapy (T12) with AAT. Patients were further asked if they were willing to use and pay out-of-pocket for on-demand treatment with phosphodiesterase-5-inhibitors (PDE-5i). Statistical analysis was performed using nonparametric hypothesis testing. The IIEF-5 score at T12 was significantly decreased compared with T0 (p < .001). Subjective patient satisfaction regarding their sexual lives was associated with higher IIEF-5 scores at both time points (p = .006 and p = .03, respectively). At T12, subjective sexual contentment showed a nonsignificant trend towards decline (p = .074). Patients who opted for medical treatment of ED showed significantly better IIEF-5 scores at both time points compared with the rest of the cohort (p < .001 and p = .005, respectively). In summary, AAT seems to have a negative effect on erectile function in RCC patients, however, the role of psychosocial issues warrants further elucidation. Affected patients may benefit from a proactive approach promoting medical treatment of erectile dysfunction during AAT.

Erectile Dysfunction after Kidney Transplantation

Patients with kidney transplantation often have a worse quality of life than the general population. One of the reasons for this, in male patients, is the high prevalence of erectile dysfunction. This is mainly due to the presence of comorbidities, surgery for kidney transplantation, adverse drug effects, psychological changes related to chronic disease, as well as hyperprolactinemia and hypogonadism. Whenever these endocrine dysfunctions occur after kidney transplantation, they must be corrected with appropriate treatment, i.e., testosterone replacement therapy. Administration of the phosphodiesterase-5 inhibitor (PDE5i) sildenafil at the recommended posology does not significantly alter the pharmacokinetics of the calcineurin inhibitors cyclosporin A or tacrolimus and does not impair kidney allograft function. Tacrolimus increases the peak concentration and prolongs the half-life of PDE5i in kidney transplant patients and, therefore, daily administration cannot be recommended due to the significant drop in blood pressure. Intracavernous injection or topical application of alprostadil can be a second-line option for the treatment of erectile dysfunction after kidney transplantation, which does not alter cyclosporine concentrations and does not deteriorate kidney function. Finally, penile prostheses can be successfully implanted following pelvic organ transplantation after eliminating the risk of infection associated with surgery.

New insights into the role of mTORC1 in male fertility in zebrafish

Mechanistic target of rapamycin complex 1 (mTORC1) plays crucial roles in male fertility. In mammals, deregulation of mTORC1 led to disordered spermatogonia proliferation and spermatogenesis, which eventually caused infertility in males. However, its roles in male fertility of non-mammalian species remain unclarified. In the present study, it was found that treatment of rapamycin, an mTORC1 inhibitor, resulted in infertility with decreased milt production and sperm motility in zebrafish. However, it is surprising to find that spermatogenesis was normal in these fish. All types of germ cells were found and the proliferation of spermatogonia and spermatocyte were normal. These results suggested that maturation of sperm may be impaired in males treated with rapamycin. Increased apoptosis was found surrounding the lumen containing spermatozoa, implicating a loss of Sertoli cells in testes treated with rapamycin. Moreover, LH/hCG mediated up-regulation of steroidogenic genes was abolished. The expression of npr and ar induced by LH/hCG was also blocked, which further suppressed the signaling of progestin and androgen. Collectively, mTORC1 maintains male fertility via different mechanisms in fish and mammals. mTORC1 is dispensable for spermatogenesis in zebrafish, but possibly supports the maintenance of Sertoli cells and mediates the signaling of hormones, which are crucial for sperm maturation.

Mechanistic target of rapamycin (mTOR) implicated in plasticity of the reproductive axis during social status transitions

The highly conserved brain-pituitary-gonadal (BPG) axis controls reproduction in all vertebrates, so analyzing the regulation of this signaling cascade is important for understanding reproductive competence. The protein kinase mechanistic target of rapamycin (mTOR) functions as a conserved regulator of cellular growth and metabolism in all eukaryotes, and also regulates the reproductive axis in mammals. However, whether mTOR might also regulate the BPG axis in non-mammalian vertebrates remains unexplored. We used complementary experimental approaches in an African cichlid fish, Astatotilapia burtoni, to demonstrate that mTOR is involved in regulation of the brain, pituitary, and testes when males rise in rank to social dominance. mTOR or downstream components of its signaling pathway (p-p70S6K) were detected in gonadotropin-releasing hormone (GnRH1) neurons, the pituitary, and testes. Transcript levels of mtor in the pituitary and testes also varied when reproductively-suppressed subordinate males rose in social rank to become dominant reproductively-active males, a transition similar to puberty in mammals. Intracerebroventricular injection of the mTORC1 inhibitor, rapamycin, revealed a role for mTOR in the socially-induced hypertrophy of GnRH1 neurons. Rapamycin treatment also had effects at the pituitary and testes, suggesting involvement of the mTORC1 complex at multiple levels of the reproductive axis. Thus, we show that mTOR regulation of BPG function is conserved to fishes, likely playing important roles in regulating reproduction and fertility across all male vertebrates.

Prospective Study on Sexual Dysfunction in Male Chinese Liver Transplant Recipients

In patients with end-stage liver disease, hypogonadism and erectile dysfunction are often seen. This study was to determine the incidence of erectile dysfunction before and after liver transplantation (LT) with correlation to change in sex hormone levels from a Chinese cohort. This prospective longitudinal study was registered with The University of Hong Kong Clinical Trials Centre (HKUCTR-1563). The Institutional Review Board approval number is UW-12-273. The study period was from January 2012 to December 2016. Adult male patients with end-stage liver disease enlisted for LT were recruited on informed written consent. All recruited patients were to complete a cross-sectional cohort questionnaire—International Index of Erectile Function, version 5 (IIEF5)—and to receive serum sex hormone checks before and after LT. Twenty-eight patients who underwent LT were included in the analysis. The included patients had significantly reduced prolactin (p < .001) and 17-beta-estradiol (p = .024) after LT. There was also a significant drop of IIEF5 score at 1 month after LT, but the score returned to pre-LT level at 6 months. This study demonstrated that there was improvement in sex hormone levels after LT, namely, normalization of estradiol level and lowering of prolactin and progesterone levels. However, improvement in sex hormone levels did not translate into improvement of erectile dysfunction.

Pooled analysis of menstrual irregularities from three major clinical studies evaluating everolimus for the treatment of tuberous sclerosis complex

Objectives

To determine the impact of everolimus on female fertility, including menstrual irregularities, secondary amenorrhea, and luteinizing and follicle stimulating hormone levels in female patients.

Design

A pooled analysis from 3 prospective studies consisting of a core phase (≥6 months) and a long-term follow-up open-label extension.

Setting

One phase 2 single-center and two phase 3 multicenter studies.

Participants

Data were obtained from female participants, restricted to those between 10 and 55 years of age, during 1 of 3 of the described clinical trials of everolimus. Patients had received ≥ 1 dose of everolimus.

Main outcome measures

Incidence of fertility events.

Results

A total of 43/112 patients (38.4%) experienced at least 1 menstrual irregularity. The most common events were amenorrhea (24.1%) and irregular menstruation (17.0%). Seven patients (6.3%) experienced grade 3/4 amenorrhea. When only the longest duration period of amenorrhea for each patient was considered, the median duration was 291 days. Fifteen patients attained menarche during the treatment period in any of the pooled studies. The mean age of menarche for this group was 12.4 years, similar to that of patients who were postmenarche at study entry (12.2 years). A total of 19/92 patients (20.7%) who were postmenarche at baseline or during the study experienced an irregular menstruation event. An increased luteinizing hormone level was reported as an adverse event in 3/112 patients (3%), and follicle-stimulating hormone levels were within normal limits for these patients.

Conclusions

No new safety concerns emerged regarding endocrine function and menstruation in female patients with tuberous sclerosis complex–associated subependymal giant cell astrocytoma or angiomyolipoma, who were receiving everolimus.

Trial registration

ClinicalTrials.govNCT00411619, NCT00789828, NCT00790400

The Effect of Targeted Therapy for Genitourinary Malignancies on Sexual Function and Fertility

PURPOSE OF REVIEW

Targeted therapy for genitourinary cancer is being used at an increasing rate. These medications show great survival benefit but are relatively lacking in long-term adverse effect data. With increasing survivability, measures to improve quality of life must be considered for GU cancer and a large proponent of this is sexual function.

RECENT FINDINGS

mTOR inhibitors have shown an effect on testosterone levels and may have a link to abnormal semen parameters. Tyrosine kinase inhibitors (TKIs) have shown no adverse sexual outcomes in the literature. There are laboratory links to tyrosine kinases having a beneficial effect on erectile and sexual function. Possible sexual side effects must be discussed with patients receiving a diagnosis of cancer. Further research is required to determine the exact mechanisms and outcomes of sexual function with new and emerging targeted therapy.

Inhibition of mTOR pathway decreases the expression of pre-meiotic and meiotic markers throughout postnatal development and in adult testes in mice

Rapamycin (mTOR inhibitor) has been reported to have negative effect on human male gonadal function. Previously, we showed that mTOR signalling molecules are expressed during early spermatogenesis in mice. The objective of this study was to investigate the role of mTOR signalling in meiosis both during the first wave of spermatogenesis and also during adult spermatogenesis. Day 5 post-partum mice were administered rapamycin and retinoic acid (RA; a Stra8 activator), and expression of p-p70S6K and Stra8 proteins was evaluated. p-p70S6K and Stra8 protein expressions decreased in post-natal testes after rapamycin treatment. Stra8 protein expression increased after RA and rapamycin+RA administrations in post-natal testes. In adult mice, rapamycin was administrated for 1 or 4 weeks. Morphological analysis for testicular damage and TUNEL assay was performed. After rapamycin administration, germ cell loss increased in adult testes. Ultrastructural analysis revealed disorganised testicular morphology and vacuolisation. The number of apoptotic germ cells increased after 4 weeks rapamycin administration. Stra8 and Dmc1 expressions decreased in 4 weeks rapamycin group, whereas Sycp3 and VASA expression did not change. Our findings suggest that mTOR pathway has an important role in meiotic progress of male germ cells both during first wave of spermatogenesis and in adult mice.

Management of everolimus-associated adverse events in patients with tuberous sclerosis complex: a practical guide

Tuberous sclerosis complex (TSC) is a genetic disorder characterised by highly variable comorbid dysfunction and subsequent morbidity. The mTOR inhibitor everolimus is indicated for the treatment of adult TSC patients with renal angiomyolipomas (AMLs) and for subependymal giant astrocytoma (SEGA) in both adults and children, based on data from the EXIST-1 and EXIST-2 trials. However, due to the historical predominance of everolimus in the oncology setting, some physicians who treat TSC patients may be unfamiliar with everolimus-associated adverse events (AEs) and appropriate management strategies. This article aims to serve as a resource for specialists including nephrologists, paediatricians, neurologists and geneticists who require practical guidance on the management of events such as non-infectious pneumonitis, rash, stomatitis, infections, and renal AEs. Additional consideration is given to drug interactions, hepatic impairment, fertility, and sexual maturation. Since patients with TSC receive clinical benefit from continued therapy, it is important that everolimus-related events are dealt with appropriately through strategies such as dose modification, interruption, the provision of supportive care, regular monitoring, and patient education.

Mammalian target of rapamycin (mTOR): a central regulator of male fertility?

Mammalian target of rapamycin (mTOR) is a central regulator of cellular metabolic phenotype and is involved in virtually all aspects of cellular function. It integrates not only nutrient and energy-sensing pathways but also actin cytoskeleton organization, in response to environmental cues including growth factors and cellular energy levels. These events are pivotal for spermatogenesis and determine the reproductive potential of males. Yet, the molecular mechanisms by which mTOR signaling acts in male reproductive system remain a matter of debate. Here, we review the current knowledge on physiological and molecular events mediated by mTOR in testis and testicular cells. In recent years, mTOR inhibition has been explored as a prime strategy to develop novel therapeutic approaches to treat cancer, cardiovascular disease, autoimmunity, and metabolic disorders. However, the physiological consequences of mTOR dysregulation and inhibition to male reproductive potential are still not fully understood. Compelling evidence suggests that mTOR is an arising regulator of male fertility and better understanding of this atypical protein kinase coordinated action in testis will provide insightful information concerning its biological significance in other tissues/organs. We also discuss why a new generation of mTOR inhibitors aiming to be used in clinical practice may also need to include an integrative view on the effects in male reproductive system.

Immunosuppressants and Male Reproduction

Prolonged use of immunosuppressant medications is occasionally seen in infertile men with chronic inflammatory conditions; autoimmune disorders; or an organ or hematopoietic stem cell transplant. Chronic inflammation impacts negatively on male reproductive endpoints, so immunosuppressant therapy can produce improvements. Corticosteroids have been used to treat antisperm antibodies and even as an empirical treatment for male infertility in general. Trials of these methods have provided mixed results on semen quality and fertility, with improvement, no change and negative effects reported by different investigators. In a substantial number of observational studies, patients on long-term therapy with prednisone for chronic inflammatory disease, testosterone levels were lower compared to untreated controls, though randomized controlled trials have not been conducted. Similarly decreases in testosterone have been reported in men receiving corticosteroids to minimize transplant rejection; however, most were treated with multiple immunosuppressive medications that may have contributed to this effect. A large number of trials of healthy men treated with corticosteroids have shown some disruption in reproductive hormone levels, but other studies reported no effect. Studies in monkeys, rats (at human equivalent dose), cattle, sheep, and horses have shown endocrine disruption, including low testosterone with dexamethasone treatment. Of the cytostatic immunosuppressives, which have high potential for cellular damage, cyclophosphamide has received the most attention, sometimes lowering sperm counts significantly. Methotrexate may decrease sperm numbers in humans and has significant negative impacts in rodents. Other chemotherapeutic drugs used as immunosuppressants are likely to impact negatively on male fertility endpoints, but few data have been collected. The TNF-α Inhibitors have also received little experimental attention. There is some evidence that the immunophilin modulators: cyclosporine, sirolimus, and everolimus cause endocrine disruption and semen quality impairment. As we review in this chapter, results in experimental species are concerning, and well-designed studies are lacking for the effects of these medications on reproductive endpoints in men.

HCG-mediated activation of mTORC1 signaling plays a crucial role in steroidogenesis in human granulosa lutein cells

Luteinizing hormone/human chorionic gonadotropin stimulates progesterone biosynthesis in the corpus luteum by activating cyclic adenosine monophosphate/protein kinase A cascade. Recent studies have shown that cyclic adenosine monophosphate-mediated activation of protein kinase A interacts with the mammalian target of rapamycin signaling pathways. Furthermore, the use of mammalian target of rapamycin inhibitors for immunosuppression in transplant patients has shown adverse effects in reproductive functions. This study examined whether the mammalian target of rapamycin pathway plays any role in luteinizing hormone-mediated regulation of progesterone production. Human granulosa lutein cells were isolated from follicular aspirates of women undergoing in vitro fertilization. Cells were cultured for 72 h and treated with human chorionic gonadotropin (50 ng/ml) for different time periods with or without pretreatment with mammalian target of rapamycin complex 1 inhibitor, rapamycin, (20 nM) for 1 h. Expression of steroidogenic enzymes, including steroidogenic acute regulatory protein, cholesterol side chain cleavage enzyme, and 3β-hydroxysteroid dehydrogenase type 1 messenger RNA, were examined by real-time polymerase chain reaction after 6 h of human chorionic gonadotropin treatment. Expressions of phospho-ribosomal protein S6 kinase and cholesterol side chain cleavage enzyme were analyzed after 15 min and 24 h of human chorionic gonadotropin treatment, respectively. Progesterone production was analyzed by an enzyme immunoassay kit after human chorionic gonadotropin (50 ng/ml) or forskolin (10 μM) treatment for 24 h. Treatment with human chorionic gonadotropin increased the expression of downstream targets of mammalian target of rapamycin complex 1, as well as cholesterol side chain cleavage enzyme, 3β-hydroxysteroid dehydrogenase type 1 and steroidogenic acute regulatory protein messenger RNAs. These increases were inhibited by rapamycin pretreatment. Increased progesterone production in response to treatment with human chorionic gonadotropin or forskolin was also blocked by rapamycin pretreatment. Our findings support a role for mammalian target of rapamycin complex 1 in regulating steroidogenesis in human granulosa lutein cells.

mTOR Regulates Gap Junction Alpha-1 Protein Trafficking in Sertoli Cells and Is Required for the Maintenance of Spermatogenesis in Mice

The mammalian target of rapamycin (Mtor) gene encodes a serine/threonine kinase that acts as a master regulator of processes as diverse as cell growth, protein synthesis, cytoskeleton reorganization, and cell survival. In the testis, physiological roles for Mtor have been proposed in perinatal Sertoli cell proliferation and blood-testis barrier (BTB) remodeling during spermatogenesis, but no in vivo studies of Mtor function have been reported. Here, we used a conditional knockout approach to target Mtor in Sertoli cells. The resulting Mtor(flox/flox); Amhr2(cre/+) mice were characterized by progressive, adult-onset testicular atrophy associated with disorganization of the seminiferous epithelium, loss of Sertoli cell polarity, increased germ cell apoptosis, premature release of germ cells, decreased epididymal sperm counts, increased sperm abnormalities, and infertility. Histopathologic analysis and quantification of the expression of stage-specific markers showed a specific loss of pachytene spermatocytes and spermatids. Although the BTB and the ectoplasmic specializations did not appear to be altered in Mtor(flox/flox);Amhr2(cre/+) mice, a dramatic redistribution of gap junction alpha-1 (GJA1) was detected in their Sertoli cells. Phosphorylation of GJA1 at Ser373, which is associated with its internalization, was increased in the testes of Mtor(flox/flox); Amhr2(cre/+) mice, as was the expression and phosphorylation of AKT, which phosphorylates GJA1 at this site. Together, these results indicate that Mtor expression in Sertoli cells is required for the maintenance of spermatogenesis and the progression of germ cell development through the pachytene spermatocyte stage. One mechanism of mTOR action may be to regulate gap junction dynamics by inhibiting AKT, thereby decreasing GJA1 phosphorylation and internalization. mTOR regulates gap junction alpha-1 protein distribution in Sertoli cells and is necessary for progression through the pachytene spermatocyte stage.

Everolimus and sirolimus in transplantation-related but different

INTRODUCTION

The inhibitors of the mammalian target of rapamycin (mTOR) sirolimus and everolimus are used not only as immunosuppressants after organ transplantation in combination with calcineurin inhibitors (CNIs) but also as proliferation signal inhibitors coated on drug-eluting stents and in cancer therapy. Notwithstanding their related chemical structures, both have distinct pharmacokinetic, pharmacodynamic and toxicodynamic properties.

AREAS COVERED

The additional hydroxyethyl group at the C(40) of the everolimus molecule results in different tissue and subcellular distribution, different affinities to active drug transporters and drug-metabolizing enzymes as well as differences in drug-target protein interactions including a much higher potency in terms of interacting with the mTOR complex 2 than sirolimus. Said mechanistic differences as well as differences found in clinical trials in transplant patients are reviewed.

EXPERT OPINION

In comparison to sirolimus, everolimus has higher bioavailability, a shorter terminal half-life, different blood metabolite patterns, the potential to antagonize the negative effects of CNIs on neuronal and kidney cell metabolism (which sirolimus enhances), the ability to stimulate mitochondrial oxidation (which sirolimus inhibits) and to reduce vascular inflammation to a greater extent. A head-to-head, randomized trial comparing the safety and tolerability of these two mTOR inhibitors in solid organ transplant recipients is merited.

[Management of side effects of targeted therapies in renal cancer: sexual disorders]

Since sexual disorders were not specifically studied in the principal series, epidemiological data is scarce. Nevertheless, in practice, when sexuality is dealt with during the monitoring of patients undergoing targeted therapies, more than half of the patients questioned say that they attach importance to their quality of sex life, despite the severity of their metastatic renal cancer. At the start of treatment, it is therefore important to inform patients of the possible occurrence of problems and to encourage them to report them. During treatment, screening for sexual disorders by questioning is desirable: desire, lubrication, dyspareunia, erectile dysfunction. In the event of the onset of a sexual disorder during treatment, it is not usually necessary to stop or modify the treatment. Therapeutic measures depend on the discomfort felt and are under the control of the specialist: erectile dysfunction, male libido disorders, vaginal dryness and vulvovaginitis. A consultation with an oncology psychologist and/or sex therapist is useful, if possible with the partner, based on the impact of the sexual problems.

Inhibition of mammalian target of rapamycin signaling pathway decreases retinoic acid stimulated gene 8 expression in adult mouse testis

OBJECTIVE

To evaluate the expression of mammalian target of rapamycin (mTOR) pathway molecules in mouse spermatogenesis and as well as its role during proliferation and meiotic initiation of spermatogenic cells.

DESIGN

Experimental animal study.

SETTING

University.

ANIMAL(S)

C57Balb-C adult male mice.

INTERVENTION(S)

Expressions of mTOR signaling pathway proteins in adult testis were evaluated. Then the effect of inhibition of this pathway on proliferation and differentiation of spermatogonial stem cells was investigated using seminiferous tubule culture.

MAIN OUTCOME MEASURE(S)

Immunohistochemistry was performed to evaluate the expressions of mTOR signaling pathway proteins. To inhibit mTOR signaling pathway by rapamycin, seminiferous tubule culture was done. Viability assay and terminal deoxynucleotidyl transferase dUTP nick end labeling was performed to evaluate the culture conditions and to examine cell death, respectively. Western blot was used to determine the expressions of the PCNA, STRA8, and VASA proteins.

RESULT(S)

Our results showed that spermatogonial stem cells and preleptotene spermatocytes express total mTOR, p-mTOR, total p70S6K, p-p70S6K, and p-4EBP1. Expressions of p-p70S6K, p-4EBP1, PCNA, and STRA8 decreased significantly in the rapamycin-treated group, where no difference was observed in VASA expression. Cell viability and the number of apoptotic cells were similar for all groups.

CONCLUSION(S)

Our findings suggest that the mTOR signaling pathway may have role in the proliferation and stimulation of meiotic initiation of spermatogonial stem cells. To the best of our knowledge, this is the first ex vivo study that reports the function of the mTOR pathway in adult mouse spermatogenesis.

mTOR inhibitors in pediatric kidney transplantation

The mammalian target of the rapamycin (mTOR) inhibitors sirolimus and everolimus are increasingly being used in pediatric kidney transplantation in different combinations and doses. Several studies have shown beneficial effects of using mTOR inhibitors in children after pediatric renal transplantation. A switch to a low-dose calcineurin inhibitor (CNI) and mTOR inhibitor has been proven to stabilize the glomerular filtration rate. Additionally, de novo studies using a low-dose CNI and an mTOR inhibitor have shown good graft survival and a low number of rejections. Side effects of mTOR inhibitors, such as hyperlipidemia, wound healing problems, and proteinuria, mainly occur if high doses are given and if treatment is not combined with a CNI. Lower doses of mTOR inhibitors do not result in growth impairment or reduced testosterone levels. Treatment with mTOR inhibitors is also associated with a lower number of viral infections, especially cytomegalovirus. Due to their antiproliferative effect, mTOR inhibitors could theoretically reduce the risk of post-transplant lymphoproliferative disease. mTOR inhibitors, especially in combination with low-dose CNIs, can safely be used in children after kidney transplantation as de novo therapy or for conversion from CNI- and mycophenolate mofetil-based regimens.

Growing experience with mTOR inhibitors in pediatric solid organ transplantation

Controlled trials of mTOR inhibitors in children following solid organ transplantation are scarce, although evidence from prospective single-arm studies is growing. Everolimus with reduced CNI therapy has been shown to be efficacious and safe in de novo pediatric kidney transplant patients in prospective trials. Prospective and retrospective data in children converted from CNI therapy to mTOR inhibition following kidney, liver, or heart transplantation suggest preservation of immunosuppressive efficacy. Good renal function has been maintained when mTOR inhibitors are used de novo in children following kidney transplantation or after conversion to mTOR inhibition with CNI minimization. mTOR inhibition with reduced CNI exposure is associated with a low risk for developing infection in children. Growth and development do not appear to be impaired during low-dose mTOR inhibition, but more studies are required. No firm conclusions can be drawn as to whether mTOR inhibitors should be discontinued in children requiring surgical intervention or whether mTOR inhibition delays progression of hepatic fibrosis after pediatric liver transplantation. In conclusion, current evidence suggests that use of mTOR inhibitors in children undergoing solid organ transplantation is efficacious and safe, but a number of issues remain unresolved and further studies are required.

Systemic and nonrenal adverse effects occurring in renal transplant patients treated with mTOR inhibitors

The mammalian target of rapamycin inhibitors (mTOR-I), sirolimus and everolimus, are immunosuppressive drugs largely used in renal transplantation. The main mechanism of action of these drugs is the inhibition of the mammalian target of rapamycin (mTOR), a regulatory protein kinase involved in lymphocyte proliferation. Additionally, the inhibition of the crosstalk among mTORC1, mTORC2, and PI3K confers the antineoplastic activities of these drugs. Because of their specific pharmacological characteristics and their relative lack of nephrotoxicity, these inhibitors are valid option to calcineurine inhibitors (CNIs) for maintenance immunosuppression in renal transplant recipients with chronic allograft nephropathy. However, as other immunosuppressive drugs, mTOR-I may induce the development of several adverse effects that need to be early recognized and treated to avoid severe illness in renal transplant patients. In particular, mTOR-I may induce systemic nonnephrological side effects including pulmonary toxicity, hematological disorders, dysmetabolism, lymphedema, stomatitis, cutaneous adverse effects, and fertility/gonadic toxicity. Although most of the adverse effects are dose related, it is extremely important for clinicians to early recognize them in order to reduce dosage or discontinue mTOR-I treatment avoiding the onset and development of severe clinical complications.

The impact of sirolimus on sex hormones in male adolescent kidney recipients

While it is known that sirolimus affects sex hormones in adult kidney transplant patients, there is a scarcity of data on its effects on sex hormone levels in adolescent kidney recipients. The objective of this study is to describe the impact of sirolimus on the sex hormones in this patient population. This is a retrospective review of male adolescent renal transplant patients transitioned to sirolimus. Baseline and subsequent annual testosterone levels were collected. Linear regression was undertaken to determine the predictors of testosterone levels. Four African Americans and 11 Caucasians, median age of 15 yr (11-18) in 2008, were included. Mean time post-transplant was 81 ± 37 months. Mean testosterone values were the following: 336 ± 135 ng/dL (n = 8) at baseline, 349 ± 130 ng/dL (n = 15) one yr later, and 360 ± 132 ng/dL (n = 13) two yr later (normal range for adult males: 350-970 ng/dL). Seven (47%) patients experienced a decrease in testosterone levels. Time on sirolimus was associated with decreased testosterone (r = 0.643, p = 0.010). Testosterone levels in pubertal male kidney transplant recipients on sirolimus may be suppressed, especially if they have been treated with sirolimus for several years. These data need to be confirmed in a larger study.

Improved erectile function and sex hormone profiles in male Chinese recipients of kidney transplantation

BACKGROUND

Few studies have reported the relationship between duration of dialysis and effect of kidney transplantation on sex hormone levels and erectile dysfunction (ED) in Chinese patients.

METHODS

Our study included 24 patients with uremia who underwent kidney transplantation. Erectile function in these patients was assessed using the 5-item version of the International Index of Erectile Function (IIEF-5), and serum sex hormone levels were measured pre- and post-transplantation. Post-transplantation changes in IIEF-5 scores were analyzed according to duration of dialysis.

RESULTS

Twenty-one (87.5%) and 11 (45.9%) of the 24 patients suffered from varying degrees of ED during the pre- and post-transplantation periods, respectively. The pre- vs. post-transplantation IIEF-5 scores were significantly different (p < 0.05) among patients who had undergone dialysis for less than six months. Following transplantation, serum levels of prolactin and β-estradiol decreased significantly (24.35 ± 11.62 vs. 13.93 ± 7.16 ng/mL, p = 0.027; 42.20 ± 15.04 vs. 17.7 ± 7.15 pg/mL, p = 0.000, respectively), whereas levels of testosterone increased (3.07 ± 0.94 vs. 6.54 ± 3.14 ng/mL, p = 0.004).

CONCLUSIONS

Successful kidney transplantation can significantly ameliorate ED in Chinese patients, especially in individuals with a shorter time on dialysis. Changes in sex hormone levels may contribute to this improvement in ED.

Tacrolimus and sirolimus induce reproductive abnormalities in female rats

BACKGROUND

Immunosuppression medications contribute to posttransplant diabetes mellitus in patients and can cause insulin resistance in male rats. Tacrolimus (TAC)-sirolimus (SIR) immunosuppression is also associated with appearance of ovarian cysts in transplant patients. Because insulin resistance is observed in patients with polycystic ovary syndrome, we hypothesized that TAC or SIR may induce reproductive abnormalities.

METHODS

We monitored estrus cycles of adult female rats treated daily with TAC, SIR, and combination of TAC-SIR, or diluent (control) for 4 weeks. Animals were then challenged with oral glucose to determine their glucose and insulin responses, killed, and their blood and tissues, including ovaries and uteri harvested.

RESULTS

TAC and TAC-SIR treatments increased mean random glucose concentrations (P<0.05). TAC, SIR, and TAC-SIR treatments also increased the glucose response to oral glucose challenge (P<0.05). The insulin response to glucose was significantly higher in rats treated with SIR compared with TAC (P<0.05). TAC, SIR and TAC-SIR treatments reduced number of estrus cycles (P<0.05). The ovaries were smaller after SIR and TAC-SIR treatment compared with controls. The TAC and TAC-SIR treatment groups had fewer preovulatory follicles. Corpora lutea were present in all groups. Ovarian aromatase expression was reduced in the SIR and TAC-SIR treatment groups. A significant (P<0.05) reduction in uterine size was observed in all treatment groups when compared with controls.

CONCLUSION

In a model of immunosuppressant-induced hyperglycemia, both TAC and SIR induced reproductive abnormalities in adult female rats, likely through different mechanisms.

Sexual dysfunction in chronic liver disease: is liver transplantation an effective cure?

The goal of liver transplantation is not only to ensure patient long-term survival but also to offer the opportunity to achieve psychologic and physical integrity. Quality of life after liver transplantation may be affected by unsatisfactory sexual function. Before liver transplantation, sexual dysfunction and sex hormone disturbances are reported in men and women mainly due to abnormality of physiology of the hypothalamic-pituitary-gonadal axis and, in some cases, origin of liver disease. Successful liver transplantation should theoretically restore hormonal balance and improve sexual function both in men and women, thus improving the reproductive performance. However, after transplantation, up to 25% of patients report persistent sexual dysfunction, and approximately one third of patients describe the appearance of de novo sexual dysfunction. Despite the described high prevalence of this condition, epidemiologic data are relatively scant. Further studies on pathophysiology and risk factors in the field of sexual function after liver transplantation along with new strategies to support and inform patients on the waiting list and after surgery are needed.

Recommendations for the assessment and reporting of multivariable logistic regression in transplantation literature

Multivariable logistic regression is an important method to evaluate risk factors and prognosis in solid organ transplant literature. We aimed to assess the quality of this method in six major transplantation journals. Eleven analytical criteria and four documentation criteria were analyzed for each selected article that used logistic regression. A total of 106 studies (6%) out of 1,701 original articles used logistic regression analyses from January 1, 2005 to January 1, 2006. The analytical criteria and their respective reporting percentage among the six journals were: Linearity (25%); Beta coefficient (48%); Interaction tests (19%); Main estimates (98%); Ovefitting prevention (84%); Goodness-of-fit (3.8%); Multicolinearity (4.7%); Internal validation (3.8%); External validation (8.5%). The documentation criteria were reported as follows: Selection of independent variables (73%); Coding of variables (9%); Fitting procedures (49%); Statistical program (65%). No significant differences were found among different journals or between general versus subspecialty journals with respect to reporting quality. We found that the report of logistic regression is unsatisfactory in transplantation journals. Because our findings may have major consequences for the care of transplant patients and for the design of transplant clinical trials, we recommend a practical solution for the use and reporting of logistic regression in transplantation journals.

Sexual dysfunction after liver transplantation

1. The goal of liver transplantation is not only to ensure the survival of patients but also to offer patients the opportunity to achieve a good balance between the functional efficacy of the graft and their psychological and physical integrity. The quality of life after transplantation may be affected by unsatisfactory sexual activity and reproductive performance. 2. Sexual dysfunction and sex hormone disturbances are widely reported in men and women with chronic liver disease before liver transplantation. 3. Successful liver transplantation should lead to improvements in sexual function and sex hormone disturbances in both men and women, therefore improving reproductive performance, but immunosuppressive drugs may interfere with hormone metabolism. 4. Pregnancy is often successful after liver transplantation, despite the potentially toxic effects of immunosuppressive drug therapy, but fetal and maternal outcomes should be regularly assessed. 5. More detailed and comprehensive data are needed in the field of sexual function after transplantation, and new strategies are needed to support and inform patients on the waiting list and after liver transplantation.

Gonadal dysfunction and infertility in kidney transplant patients receiving sirolimus

Sirolimus is an immunosupressor of the mammalian target of rapamycin inhibitors (mTOR-I) group. Recent studies have emphasized a potential impact of sirolimus on male gonadal function. We report our clinical experience with sirolimus-induced gonadal dysfunction and infertility in both male and female kidney transplant patients. Of the 170 kidney transplant patients, nine (5.3%) patients (six males and three females) were receiving sirolimus. Follow-up data for two male patients were not available. The one unmarried female patient developed amenorrhea post-transplantation and had resumption of her menstrual cycles after discontinuation of sirolimus. The remaining six married patients (four males and two females), who all had fathered or conceived children in the pre-transplantation period, developed gonadal dysfunction and infertility on average 5-12 months after transplantation. Sirolimus was discontinued in all four male patients with full recovery of the oligo/azospermia and restoration of fertility. Both married female patients developed amenorrhea post-transplantation. Sirolimus was discontinued in one female patient with resumption of her menstrual cycles. In this small population of patients treated with sirolimus, the prevalence rate of reversible gonadal dysfunction and infertility was significant in both males and females. Infertility secondary to sirolimus is under-diagnosed and should be studied further.

Erectile dysfunction in liver transplant patients

The objectives of the study were to determine the frequency of erectile dysfunction (ED) after liver transplantation (LT) and discuss potential risk factors. Of 123 eligible LT men, 98 (79.7%) responded to a questionnaire about sexual function at a mean time posttransplant of 5.4 +/- 4.0 years (1.0-21). Erection was evaluated using the five-question international index for erectile function score, and sexual satisfaction by the patient-baseline treatment-satisfaction status (TSS) score. Questions also focused on patient perception of changes overtime. We found that after LT, the proportion of sexually inactive men decreased from 29% to 15% (p = 0.01), but the proportion of men with ED remained unchanged. The absence of sexual activity was associated with pretransplant sexual inactivity (p = 0.001), age (p = 0.008), cardiovascular disease (p = 0.03), use of diuretics (p = 0.04), anticoagulants (p = 0.001), statins (p = 0.01) and treatment for diabetes (p = 0.03). Cardiovascular disease (p = 0.05), posttransplantation diabetes (p = 0.04), alcohol abuse (p = 0.03), antidepressants (p = 0.05) and angiotensin II receptor blockers (p = 0.05) were associated with having ED after LT. Having a low TSS score was associated with a history of endocrine disease (p = 0.03), antidepressants (p = 0.04) and diuretics (p = 0.03). In conclusion, LT improves sexual activity, but ED is multifactorial and remains a long-term condition in the majority of patients.

Acute allograft rejection and immunosuppression: influence on endogenous melatonin secretion

Melatonin displays a dose-dependent immunoregulatory effect in vitro and in vivo. Exogenous high-dose melatonin therapy exerted an immunosuppressive effect, abrogating acute rejection (AR), significantly prolonging transplant survival. Endogenous melatonin secretion, in response to heterotopic rat cardiac allograft transplantation (Tx), was investigated during the AR response and under standardized immunosuppressive maintenance therapy with cyclosporin A (CsA) and rapamycin (RPM). Recipients of syngeneic transplants, and recipients of allogeneic grafts, either untreated or receiving immunosuppressive therapy constituted the experimental groups. Endogenous circadian melatonin levels were measured at 07:00, 19:00, and 24:00 hr, using a novel radioimmunoassay (RIA) procedure, under standardized 12-hr-light/dark-conditions (light off: 19:00 hr; light on: 07:00 hr), before and after Tx. Neither the operative trauma, nor the challenge with a perfused allograft or the AR response influenced endogenous melatonin peak secretion. Immunosuppressive therapy with CsA led to a significant increase in peak secretion, measured for days 7 (212 +/- 40.7 pg/mL; P < 0.05), 14 (255 +/- 13.9 pg/mL; P < 0.001), and 21 (219 +/- 34 pg/mL; P < 0.01) after Tx, as compared with naïve animals (155 +/- 25.8 pg/mL). In contrast, treatment with RPM significantly decreased the melatonin peak post-Tx up to day 7 (87 +/- 25.2 pg/mL; P < 0.001), compared with naïve animals (155 +/- 25.8 pg/mL). These findings imply a robust nature of the endogenous circadian melatonin secretion kinetics, even against the background of profound allogeneic stimuli. Immunosuppressive maintenance therapy with CsA and RPM modulated early melatonin secretion, indicating a specific secondary action of these drugs. Further studies are necessary to disclose the long-term effect of immunosuppressive therapy on circadian melatonin secretion in transplant recipients.

Transplant recipient renal function is donor renal mass- and recipient gender-dependent

The effect of both donor renal mass and gender on renal function, in both gender recipients, was examined. Qualifying consecutive living-donor renal transplants (n = 730) were stratified into 4 donor-recipient groups: female-female (n = 177), male-female (n = 151), female-male (n = 240), male-male (n = 162). Groups were equivalent in age, race, body mass index (BMI), match, ischemia time, operative time, and estimated glomerular filtration rate (eGFR). Female recipients had lower serum creatinine (Cr(s)). Male recipients had higher Cr(s) wherever they received a female allograft. Male recipients of male kidneys had a higher eGFR than all other groups for 3 years. Renal function of the recipient correlated with the renal mass of the donor within each group. Male and female kidneys functioned equivalently in the female-recipient environment. Large nephron-mass male donor kidneys function more poorly in female recipients. The male kidney loses 15-20 ml/min eGFR in the female host. The diminished graft function may be related to androgen deprivation. Female and male donor kidneys function equivalently in the male recipient if adjusted for renal mass transplanted. Female kidneys improve eGFR by 7-10 ml/min by being transplanted into a male environment. Donor renal mass and gender affect recipient graft function Expectations of ultimate recipient renal function should take into account both the gender and mass disparity of the donor-recipient pair.

Quality of life following organ transplantation

Organ transplantation is a procedure that can save and prolong the life of individuals with end-stage heart, lung, liver, kidney, pancreas and small bowel diseases. The goal of transplantation is not only to ensure their survival, but also to offer patients the sort of health they enjoyed before the disease, achieving a good balance between the functional efficacy of the graft and the patient's psychological and physical integrity. Quality of life (QoL) assessments are used to evaluate the physical, psychological and social domains of health, seen as distinct areas that are influenced by a person's experiences, beliefs, expectations and perceptions, and QoL is emerging as a new medical indicator in transplantation medicine too. This review considers changes in overall QoL after organ transplantation, paying special attention to living donor transplantation, pediatric transplantation and particular aspects of QoL after surgery, e.g. sexual function, pregnancy, schooling, sport and work.

Gonadal impact of target of rapamycin inhibitors (sirolimus and everolimus) in male patients: an overview

The immunosuppressive agents target of rapamycin inhibitors (TOR-I) (sirolimus, and everolimus) have been widely used in kidney transplantation for >10 years. Up to 40% of men receiving a kidney transplant are younger than 50, and fertility as well as erectile function are major concerns. In this review, we provide a synopsis of past studies focusing on gonadal function in men treated with TOR-I, mainly sirolimus, to establish what impact they have on male gonads, and which pathophysiological pathways are involved. A PubMed search for the years 1990-2006 selected articles that focused on the gonadal impact of TOR-I. Primary outcome measures were testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels. Secondary outcome measures were sexual function, fertility status and sperm parameters. Treatment with TOR-I results in a decrease in testosterone level, and an opposite increase in LH. Moreover, spermatogenesis seems to be disrupted by TOR-I and FSH levels are increased. Sirolimus and everolimus inhibit the activity of mammalian targets of rapamycin, a serine/threonine kinase involved in numerous cell-growth processes. Molecular mechanisms of action of TOR-I on the testis involve inhibition of a stem cell factor/c-kit-dependant process in spermatogonia. Preliminary results appear to show that TOR-I treatment has deleterious actions on the testis and impairs gonadal function after renal transplantation, but the impact of these effects are unknown.