Ganciclovir induces reproductive hazards in male rats after short-term exposure

"Congenital cytomegalovirus in Sub-Saharan Africa-a narrative review with practice recommendations"

Cytomegalovirus (CMV) is the most common cause of congenital infection internationally, occurring in 0.67% of births, and increasingly recognised as a major public health burden due to the potential for long-term neurodevelopmental and hearing impairment. This burden includes estimates of 10% of childhood cerebral palsy and up to 25% of childhood deafness. In Sub-Saharan Africa, where CMV-seroprevalence is almost ubiquitous, prevalence of congenital CMV (cCMV) is higher than the global average, and yet there is a dearth of research and initiatives to improve recognition, diagnosis and treatment. This narrative review outlines the epidemiology and clinical presentation of cCMV, discusses issues of case identification and treatment in Sub-Saharan Africa, and recommends a framework of strategies to address these challenges. Considering the significant burden of cCMV disease in this setting, it is undoubtably time we embark upon improving diagnosis and care for these infants.

Association between White Matter T2 Hyper-Intense Signals in Fetal Brain Magnetic Resonance Imaging and Neurodevelopment of Fetuses with Cytomegalovirus Infection

An association between subtle changes in T2 white matter hyper-intense signals (WMHSs) detected in fetal brain magnetic resonance imaging (fbMRI) and congenital cytomegalovirus (CMV) infection has been established. The research aim of this study is to compare children with congenital CMV infection with neurodevelopment outcome and hearing deficit with and without WMHSs in a historic prospective case study cohort of 58 fbMRIs. Of these, in 37 cases, fbMRI was normal (normal group) and WMHSs were detected in 21 cases (WMHS group). The median infection week of the WMHS group was earlier than the normal fbMRI group (8 and 17 weeks of gestation, respectively). The proportion of infants treated with valganciclovir in the WMHS group was distinctly higher. Hearing impairment was not significantly different between the groups. VABS scores in all four domains were within normal range in both groups. The median score of the motor skills corrected for week of infection was better in the WMHS group. A multivariate analysis using the week of infection interaction variable of WMHS and valganciclovir treatment showed better motor score outcomes in the valganciclovir treatment group despite an earlier week of infection. WMHSs were not associated with neurodevelopmental outcome and hearing deficit. In our cohort, valganciclovir treatment may have a protective effect on fetuses with WMHSs by improving neurodevelopmental outcome.

Adverse drug reactions on male fertility

For several years, fertility disorders have been on the increase worldwide. These disorders affect both sexes, but are more pronounced in men; and in half of cases the etiology is unknown. The role of drugs in male infertility has been little studied to date. Most of the available data comes from experimental animal studies, with all their limitations. With the exception of a few drugs, such as certain anticancer agents, human data are rare. This article describes the mainly drugs known to have deleterious effects on male fertility, the mechanisms leading to these effects and methods used to assess the risk of drug-induced male infertility. It underlines the need for further work in experimental research, clinical trials and post-marketing surveillance to improve our knowledge of drugs that induce male infertility. Although these adverse effects are not life-threatening, they can have a significant impact on patients' lives.

Treatment of congenital cytomegalovirus infection

Congenital cytomegalovirus (CMV) is the most common cause of congenital infection worldwide, the most common nongenetic cause of sensorineural hearing loss in children, and a cause of neurodevelopmental disorders in the brain. Infants with symptomatic congenital CMV infection may benefit from hearing and neurodevelopmental outcomes, particularly if antiviral treatment is initiated within the first month of life. Infants with life-threatening symptoms are recommended to receive 2-6 weeks of intravenous ganciclovir and then switch to oral valganciclovir, and those without life-threatening symptoms are recommended to use oral valganciclovir during the entire 6-month period. During antiviral drug treatment, absolute neutrophil count, platelet count, blood urea nitrogen, creatinine, and liver function tests were performed to identify neutropenia, thrombocytopenia, renal failure, and liver failure. This review investigated the evidence to date of treating congenital CMV infection.

Impact of endocrine disrupting chemicals and pharmaceuticals on Sertoli cell development and functions

Sertoli cells play essential roles in male reproduction, from supporting fetal testis development to nurturing male germ cells from fetal life to adulthood. Dysregulating Sertoli cell functions can have lifelong adverse effects by jeopardizing early processes such as testis organogenesis, and long-lasting processes such as spermatogenesis. Exposure to endocrine disrupting chemicals (EDCs) is recognized as contributing to the rising incidence of male reproductive disorders and decreasing sperm counts and quality in humans. Some drugs also act as endocrine disruptors by exerting off-target effects on endocrine tissues. However, the mechanisms of toxicity of these compounds on male reproduction at doses compatible with human exposure are still not fully resolved, especially in the case of mixtures, which remain understudied. This review presents first an overview of the mechanisms regulating Sertoli cell development, maintenance, and functions, and then surveys what is known on the impact of EDCs and drugs on immature Sertoli cells, including individual compounds and mixtures, and pinpointing at knowledge gaps. Performing more studies on the impact of mixtures of EDCs and drugs at all ages is crucial to fully understand the adverse outcomes these chemicals may induce on the reproductive system.

Selective Depletion of Adult GFAP-Expressing Tanycytes Leads to Hypogonadotropic Hypogonadism in Males

In adult mammals, neural stem cells are localized in three neurogenic regions, the subventricular zone of the lateral ventricle (SVZ), the subgranular zone of the dentate gyrus of the hippocampus (SGZ) and the hypothalamus. In the SVZ and the SGZ, neural stem/progenitor cells (NSPCs) express the glial fibrillary acidic protein (GFAP) and selective depletion of these NSPCs drastically decreases cell proliferation in vitro and in vivo. In the hypothalamus, GFAP is expressed by α-tanycytes, which are specialized radial glia-like cells in the wall of the third ventricle also recognized as NSPCs. To explore the role of these hypothalamic GFAP-positive tanycytes, we used transgenic mice expressing herpes simplex virus thymidine kinase (HSV-Tk) under the control of the mouse Gfap promoter and a 4-week intracerebroventricular infusion of the antiviral agent ganciclovir (GCV) which kills dividing cells expressing Tk. While GCV significantly reduced the number and growth of hypothalamus-derived neurospheres from adult transgenic mice in vitro, it causes hypogonadotropic hypogonadism in vivo. The selective death of dividing tanycytes expressing GFAP indeed results in a marked decrease in testosterone levels and testicular weight, as well as vacuolization of the seminiferous tubules and loss of spermatogenesis. Additionally, GCV-treated GFAP-Tk mice show impaired sexual behavior, but no alteration in food intake or body weight. Our results also show that the selective depletion of GFAP-expressing tanycytes leads to a sharp decrease in the number of gonadotropin-releasing hormone (GnRH)-immunoreactive neurons and a blunted LH secretion. Overall, our data show that GFAP-expressing tanycytes play a central role in the regulation of male reproductive function.

A systematic overview of the spermatotoxic and genotoxic effects of methotrexate, ganciclovir and mycophenolate mofetil

INTRODUCTION

Immunosuppressant drugs are increasingly being used in the reproductive years. Theoretically, such medications could affect fetal health either through changes in the sperm DNA or through fetal exposure caused by a presence in the seminal fluid. This systematic overview summarizes existing literature on the spermatotoxic and genotoxic potentials of methotrexate (MTX), a drug widely used to treat rheumatic and dermatologic diseases, and mycophenolate mofetil (MMF), which alone or supplemented with ganciclovir (GCV) may be crucial for the survival of organ transplants.

MATERIAL AND METHODS

The systematic overview was performed in accordance with the PRISMA guidelines: A systematic literature search of the MEDLINE and Embase databases was done using a combination of relevant terms to search for studies on spermatotoxic or genotoxic changes related to treatment with MTX, GCV or MMF. The search was restricted to English language literature, and to in vivo animal studies (mammalian species) and clinical human studies.

RESULTS

A total of 102 studies were identified, hereof 25 human and 77 animal studies. For MTX, human studies of immunosuppressive dosages show transient effect on sperm quality parameters, which return to reference values within 3 months. No human studies have investigated the sperm DNA damaging effect of MTX, but in other organs the genotoxic effects of immunosuppressive doses of MTX are fluctuating. In animals, immunosuppressive and cytotoxic doses of MTX adversely affect sperm quality parameters and show widespread genotoxic damages in various organs. Cytotoxic doses transiently change the DNA material in all cell stages of spermatogenesis in rodents. For GCV and MMF, data are limited and the results are indeterminate, for which reason spermatotoxic and genotoxic potentials cannot be excluded.

CONCLUSIONS

Data from human and animal studies indicate transient spermatotoxic and genotoxic potentials of immunosuppressive and cytotoxic doses of MTX. There are a limited number of studies investigating GCV and MMF.

Personalized-induced neural stem cell therapy: Generation, transplant, and safety in a large animal model

In this study, we take an important step toward clinical translation by generating the first canine-induced neural stem cells (iNSCs). We explore key aspects of scale-up, persistence, and safety of personalized iNSC therapy in autologous canine surgery models. iNSCs are a promising new approach to treat aggressive cancers of the brain, including the deadly glioblastoma. Created by direct transdifferentiation of fibroblasts, iNSCs are known to migrate through the brain, track down invasive cancer foci, and deliver anticancer payloads that significantly reduce tumor burden and extend survival of tumor-bearing mice. Here, skin biopsies were collected from canines and converted into the first personalized canine iNSCs engineered to carry TNFα-related apoptosis-inducing ligand (TRAIL) and thymidine kinase (TK), as well as magnetic resonance imaging (MRI) contrast agents for in vivo tracking. Time-lapse analysis showed canine iNSCs efficiently migrate to human tumor cells, and cell viability assays showed both TRAIL and TK monotherapy markedly reduced tumor growth. Using intraoperative navigation and two delivery methods to closely mimic human therapy, canines received autologous iNSCs either within postsurgical cavities in a biocompatible matrix or via a catheter placed in the lateral ventricle. Both strategies were well tolerated, and serial MRI showed hypointense regions at the implant sites that remained stable through 86 days postimplant. Serial fluid sample testing following iNSC delivery showed the bimodal personalized therapy was well tolerated, with no iNSC-induced abnormal tissue pathology. Overall, this study lays an important foundation as this promising personalized cell therapy advances toward human patient testing.

Ethical and Public Health Implications of Targeted Screening for Congenital Cytomegalovirus

Congenital cytomegalovirus (cCMV) is the most common congenital infection and is associated with sensorineural hearing loss, developmental delays, and visual impairment. The clinical presentation of cCMV is variable, and the majority (80%-90%) of newborns will never manifest any clinical symptoms. Given the clinical heterogeneity of cCMV infection, it is challenging to identify which newborns may benefit from testing. Recently, certain states have implemented a targeted screening program in which newborns who fail the newborn hearing screen are tested for cCMV. Clinicians and legislative bodies have been propelled into debates about the ethical and moral permissibility of a targeted cCMV screening approach. Those who oppose this screening approach describe undue burden on patients, families, and the health care system because the majority of newborns who fail the newborn hearing screen and have cCMV will not go on to have any sequelae related to cCMV, including hearing loss. However, those who support this screening approach cite the importance of early detection and ongoing surveillance for hearing loss and developmental delays in this high-risk group of newborns. This debate will be considered by experts in the field.

Effects of valganciclovir on spermatogenesis in renal transplant patients - results of a multicenter prospective nonrandomized study

Ganciclovir (GCV) inhibits spermatogenesis in preclinical studies but long‐term effects on fertility in renal transplant patients are unknown. In a prospective, multicenter, open‐label, nonrandomized study, male patients were assigned to Cohort A [valganciclovir (VGCV), a prodrug of GCV] (n = 38) or B (no VGCV) (n = 21) by cytomegalovirus prophylaxis requirement. Changes in semen parameters and DNA fragmentation were assessed via a mixed‐effects linear regression model accounting for baseline differences. Sperm concentration increased post‐transplant, but between baseline and treatment end (mean 164 days Cohort A, 211 days Cohort B), the model‐based change was lower in Cohort A (difference: 43.82 × 10⁶/ml; P = 0.0038). Post‐treatment, sperm concentration increased in Cohort A so that by end of follow‐up (6 months post‐treatment) changes were comparable between cohorts (difference: 2.09 × 10⁶/ml; P = 0.92). Most patients’ sperm concentration improved by end of follow‐up; none with normal baseline concentrations (≥20 × 10⁶/ml) were abnormal at end of follow‐up. Changes in seminal volume, sperm motility/morphology, DNA fragmentation, and hormone levels were comparable between cohorts at end of follow‐up. Improvement in semen parameters after renal transplant was delayed in men receiving VCGV, but 6 months post‐treatment parameters were comparable between cohorts.

Refractory Ileal Perforations in a Cytomegalovirus-Infected Premature Neonate Resolved After Ganciclovir Therapy

Severe neonatal gastrointestinal diseases such as necrotizing enterocolitis or spontaneous intestinal perforation are potentially lethal conditions which predominantly occur in preterm infants. Cytomegalovirus (CMV), which is known to cause congenital and acquired infections in the newborns, has also been implicated in such severe gastrointestinal diseases in premature infants. However, the pathogenic role of CMV and effect of antiviral therapy in severe gastrointestinal disease in premature neonates is currently unclear. We present an infant, born at 26-weeks' gestation, presented with progressive dyspepsia and abdominal distention after the closure of the symptomatic patent ductus arteriosus at the day of life (DOL) 4, requiring the emergent surgery for ileal perforation at the DOL8. After the surgery, abdominal symptoms persisted and the second emergent surgery was performed for the recurrent ileal perforation at DOL17. Even then the abdominal symptoms prolonged and pathological examination in the affected intestine at the second surgery showed CMV inclusion body. Immunoreactivity for CMV antigen was detected in the specimen at the first surgery on DOL8. Blood and urinary CMV-DNA were detected at DOL28. CMV-DNA was also detected in the dried umbilical cord which was obtained within a week from birth. A 6-week course of intravenous ganciclovir (12 mg/kg/day) was started at DOL34 and then symptoms resolved along with decreasing blood CMV-DNA. Pathological findings characteristic of CMV were not detected in the resection specimen at the ileostomy closure at DOL94. These observations indicate that anti-CMV therapy may be beneficial for some premature infants with severe CMV-associated gastrointestinal diseases and warrants further studies focusing on pathogenic role, diagnosis, treatment and prevention of this underrecognized etiology of severe gastrointestinal diseases particularly in premature neonates.

Molecular Mechanisms and Signaling Pathways Involved in Sertoli Cell Proliferation

Sertoli cells are somatic cells present in seminiferous tubules which have essential roles in regulating spermatogenesis. Considering that each Sertoli cell is able to support a limited number of germ cells, the final number of Sertoli cells reached during the proliferative period determines sperm production capacity. Only immature Sertoli cells, which have not established the blood-testis barrier, proliferate. A number of hormonal cues regulate Sertoli cell proliferation. Among them, FSH, the insulin family of growth factors, activin, and cytokines action must be highlighted. It has been demonstrated that cAMP/PKA, ERK1/2, PI3K/Akt, and mTORC1/p70SK6 pathways are the main signal transduction pathways involved in Sertoli cell proliferation. Additionally, c-Myc and hypoxia inducible factor are transcription factors which participate in the induction by FSH of various genes of relevance in cell cycle progression. Cessation of proliferation is a pre-requisite to Sertoli cell maturation accompanied by the establishment of the blood-testis barrier. With respect to this barrier, the participation of androgens, estrogens, thyroid hormones, retinoic acid and opioids has been reported. Additionally, two central enzymes that are involved in sensing cell energy status have been associated with the suppression of Sertoli cell proliferation, namely AMPK and Sirtuin 1 (SIRT1). Among the molecular mechanisms involved in the cessation of proliferation and in the maturation of Sertoli cells, it is worth mentioning the up-regulation of the cell cycle inhibitors p21Cip1, p27Kip, and p19INK4, and of the gap junction protein connexin 43. A decrease in Sertoli cell proliferation due to administration of certain therapeutic drugs and exposure to xenobiotic agents before puberty has been experimentally demonstrated. This review focuses on the hormones, locally produced factors, signal transduction pathways, and molecular mechanisms controlling Sertoli cell proliferation and maturation. The comprehension of how the final number of Sertoli cells in adulthood is established constitutes a pre-requisite to understand the underlying causes responsible for the progressive decrease in sperm production that has been observed during the last 50 years in humans.

FDA-approved medications that impair human spermatogenesis

We herein provide an overview of the single-ingredient U.S. Food and Drug Administration (FDA)-approved drugs that affect human spermatogenesis, potentially resulting in a negative impact on male fertility. To provide this information, we performed an in-depth search of DailyMed, the official website for FDA-approved drug labels. Not surprisingly, hormone-based agents were found to be the drugs most likely to affect human spermatogenesis. The next category of drugs most likely to have effects on spermatogenesis was the antineoplastic agents. Interestingly, the DailyMed labels indicated that several anti-inflammatory drugs affect spermatogenesis, which is not supported by the peer-reviewed literature. Overall, there were a total of 65 labels for drugs of various classes that showed that they have the potential to affect human sperm production and maturation. We identified several drugs indicated to be spermatotoxic in the drug labels that were not reported in the peer-reviewed literature. However, the details about the effects of these drugs on human spermatogenesis are largely lacking, the mechanisms are often unknown, and the clinical impact of many of the findings is currently unclear. Therefore, additional work is needed at both the basic research level and during clinical trials and post-marketing surveillance to fill the gaps in the current knowledge. The present findings will be of interest to physicians and pharmacists, researchers, and those involved in drug development and health care policy.

Genetic studies in mice directly link oocytes produced during adulthood to ovarian function and natural fertility

Multiple labs have reported that mammalian ovaries contain oogonial stem cells (OSCs), which can differentiate into oocytes that fertilize to produce offspring. However, the physiological relevance of these observations to adult ovarian function is unknown. Here we performed targeted and reversible ablation of premeiotic germ cells undergoing differentiation into oocytes in transgenic mice expressing the suicide gene, herpes simplex virus thymidine kinase (HSVtk), driven by the promoter of stimulated by retinoic acid gene 8 (Stra8), a germ cell-specific gene activated during meiotic commitment. Over a 21-day ablation phase induced by the HSVtk pro-drug, ganciclovir (GCV), oocyte numbers declined due to a disruption of new oocyte input. However, germ cell differentiation resumed after ceasing the ablation protocol, enabling complete regeneration of the oocyte pool. We next employed inducible lineage tracing to fate map, through Cre recombinase-mediated fluorescent reporter gene activation only in Stra8-expressing cells, newly-formed oocytes. Induction of the system during adulthood yielded a mosaic pool of unmarked (pre-existing) and marked (newly-formed) oocytes. Marked oocytes matured and fertilized to produce offspring, which grew normally to adulthood and transmitted the reporter to second-generation offspring. These findings establish that oocytes generated during adulthood contribute directly to ovarian function and natural fertility in mammals.

Effectiveness of Preemptive Therapy for Cytomegalovirus Disease in Pediatric Liver Transplantation

BACKGROUND

Most pediatric liver transplantation (LT) centers administer long courses of prophylaxis against cytomegalovirus (CMV) without evidence of benefit and with significant drug exposure and costs. We aimed at evaluating overall outcomes, direct and putative indirect effects of CMV, possible impact of viremia and risk factors for CMV infection in pediatric LT recipients managed with ganciclovir-based preemptive therapy (PET).

METHODS

The records of all the children who underwent LT between 2008 and 2014 were retrospectively analyzed.

RESULTS

One hundred children were included. Three children had CMV disease; no CMV-related death or graft loss was recorded. The only identified risk factor for CMV infection was the donor/recipient serostatus (odds ratio, 17.23; 95% confidence interval, 1.88-157.87; P = 0.012), while viremia per se did not worsen LT outcomes, such as the incidence of acute rejection, Epstein-Barr virus infection, sepsis, biliary and vascular complications, nor graft dysfunction/loss or death at 3 and 5 years after LT. When compared with a historical cohort of children receiving ganciclovir prophylaxis, PET did not differ from prophylaxis for any of the selected outcomes, but was rather associated with lower antiviral drug exposure (6.4 ± 13 days vs 38.6 ± 14 days, P < 0.0001) and cost per patient (2.2 ± 3.9 k&OV0556; vs 6.6 ± 8.2 k&OV0556;, P = 0.001).

CONCLUSIONS

PET is effective in controlling CMV in children receiving LT, with lower costs and lower exposure to antivirals.

Effects of four nucleoside analogues used as antiviral agents on rat Sertoli cells (SerW3) in vitro

Some nucleoside analogues are used to treat herpes simplex and other viral infections. They are known to impair spermatogenesis, but published data are scarce. We studied the effects of four nucleosides on SerW3 cells, a rat Sertoli cell line. Cells were cultured for 3 days in DMEM supplemented with four different concentrations of each drug. Aciclovir and ganciclovir were added at concentrations of 0.3, 1, 3 and 10 mg/l medium; penciclovir and its prodrug famciclovir were used at higher concentrations (3, 10, 30, 100 mg/l medium). After a culture period of 3 days, we analysed the expression of connexin43, N-cadherin and the cytoskeleton protein vimentin by Western blot. Aciclovir caused a clear-cut effect at the highest concentration tested (10 mg/l), which is less than the peak plasma concentration achieved in patients during intravenous therapy with the drug. Connexin43, vimentin and N-cadherin content decreased to 49.8 ± 17, 44.0 ± 4 and 75.4 ± 1.5 % of the control values, respectively (n = 3; mean ± SD). Similar effects were observed with the prodrug ganciclovir (43.2 ± 10.8; 54.1 ± 11.9; 84.4 ± 10.8 % of controls). Penciclovir caused less pronounced effects at 10 mg/l medium (82.1 ± 20.6; 90.0 ± 12.0; 76.5 ± 17.7 % of controls). Only a slight effect was observed with famciclovir. Even at a 10-fold concentration (100 mg/l), just moderate changes were induced. In summary, we observed clear-cut effects with aciclovir and ganciclovir on Sertoli cells in vitro at therapeutically relevant concentrations and identified connexin43 as the most sensitive marker.

Cytomegalovirus in immunocompromised children

PURPOSE OF REVIEW

The purpose of this study is to explore the latest developments in the risk factors, prevention and treatment of cytomegalovirus (CMV) infection in immunocompromised children, including those with congenital immunodeficiency or iatrogenic immune suppression related to solid organ transplantation (SOT) or haematopoietic cell transplantation (HCT).

RECENT FINDINGS

CMV viral load measurements now have international standards, allowing for more reliable comparison across sites and within individuals. Preemptive and prophylactic therapy with routine CMV monitoring in transplant patients has yielded significant reduction in CMV morbidity and mortality in these patients. The majority of U.S. states have adopted routine newborn screening for severe combined immunodeficiency (SCID). Viral infections, including CMV, are a major obstacle preventing optimal curative transplantation in these patients. Several new antiviral agents are currently being investigated for CMV infection in immunocompromised patients. Knowledge on CMV drug resistance in children is emerging and requires further study.

SUMMARY

Conditions that diminish cell-mediated immunity impact the development of CMV infection and disease. These conditions include certain congenital immunodeficiencies and SOT and HCT. Infants identified as having SCID should be screened for CMV risk factors. A preemptive or prophylactic strategy should be chosen for CMV management in children who are high risk posttransplantation. In those who develop disease, viral loads should be monitored and resistance testing considered if response is not deemed adequate. Oral valganciclovir is being used as an alternative to ganciclovir in children, although pharmacokinetic data are limited. Other oral antiviral agents under development are promising future options for paediatric CMV therapy.

Testicular effects following in utero exposure to the antivirals acyclovir and ganciclovir in rats

In utero exposure to the antivirals acyclovir and ganciclovir has been reported to induce gross structural defects in rat offspring. The present study investigated the effects of maternal antiviral treatment on gestation day 10 on reproductive and nonreproductive organs in male rat offspring with a particular focus on the testes. Vehicle and two doses of acyclovir and ganciclovir, 75 and 300 mg/kg, were administered to rat dams. The total doses were fractioned into three subcutaneous applications (3 × distilled water, 3 × 25 mg/kg, and 3 × 100 mg/kg) that were administered on gestation day 10 at 8:00 a.m., 1:00 p.m., and 6:00 p.m. The antiviral concentrations were measured in the serum of the dams 1 h after the last administration. Exposure to 300 mg/kg ganciclovir induced germ cell deficiency in both fetal and adult testes, an effect that was not seen in any other treatment group. Adult rats exposed in utero to this high ganciclovir dose exhibited Sertoli cell-only tubules intermingled with seminiferous tubules that displayed a normal size and normal cell counts, alterations that resemble focal Sertoli cell-only syndrome in humans. The serum concentrations of ganciclovir were markedly higher than those of acyclovir, particularly at the high dose tested. However, although 300 mg/kg acyclovir did not induce germ cell deficiency, other specific effects were seen in exposed animals, including incomplete eye opening and reduced thymus weight.

Valganciclovir for the prevention and treatment of cytomegalovirus disease in immunocompromised hosts

Valganciclovir (Valcyte, Roche), a prodrug of the deoxyguanosine analog ganciclovir (Cytovene, Roche), is indicated for induction and maintenance treatment of cytomegalovirus retinitis in patients with AIDS and for prevention of cytomegalovirus disease in selected high-risk solid organ transplant recipients. After oral administration, valganciclovir is rapidly absorbed and converted to ganciclovir by intestinal and hepatic esterases. Valganciclovir is a highly recognized substrate of the intestinal peptide transporter PEPT1, which underlies the tenfold higher bioavailability of ganciclovir after valganciclovir compared to oral ganciclovir administration. At oral dose of 900 mg, valganciclovir provides a systemic ganciclovir exposure that is comparable to intravenous ganciclovir, at the standard dose of 5 mg/kg of body weight. Subsequent phosphorylation of ganciclovir, which occurs preferentially within cytomegalovirus-infected cells, results in the active metabolite, ganciclovir triphosphate, which is responsible for suppressing viral DNA synthesis by competitively inhibiting the incorporation of the natural substrate deoxyguanosine into viral DNA and thereby, terminating cytomegalovirus replication.

Deregulated hepatic metabolism exacerbates impaired testosterone production in Mrp4-deficient mice

The physiological role of multidrug resistance protein 4 (Mrp4, Abcc4) in the testes is unknown. We found that Mrp4 is expressed primarily in mouse and human Leydig cells; however, there is no current evidence that Mrp4 regulates testosterone production. We investigated its role in Leydig cells, where testosterone production is regulated by cAMP, an intracellular messenger formed when the luteinizing hormone (LH) receptor is activated. Because Mrp4 regulates cAMP, we compared testosterone levels in Mrp4(-/-) and Mrp4(+/+) mice. Young Mrp4(-/-) mice had significantly impaired gametogenesis, reduced testicular testosterone, and disruption of Leydig cell cAMP homeostasis. Both young and adult mice had impaired testosterone production. In Mrp4(-/-) primary Leydig cells treated with LH, intracellular cAMP production was impaired and cAMP-response element-binding protein (CREB) phosphorylation was strongly attenuated. Notably, expression of CREB target genes that regulate testosterone biosynthesis was reduced in Mrp4(-/-) Leydig cells in vivo. Therefore, Mrp4 is required for normal Leydig cell testosterone production. However, adult Mrp4(-/-) mice are fertile, with a normal circulating testosterone concentration. The difference is that in 3-week-old Mrp4(-/-) mice, disruption of gonadal testosterone production up-regulates hepatic Cyp2b10, a known testosterone-metabolizing enzyme. Therefore, defective testicular testosterone production de-regulates hepatic Cyp-mediated testosterone metabolism to disrupt gametogenesis. These findings have important implications for understanding the side effects of therapeutics that disrupt Mrp4 function and are reported to alter androgen production.

[Congenital cytomegalovirus infection: is serological screening during pregnancy necessary?]

Primary cytomegalovirus (CMV) infection occurs during pregnancy in 1% to 4% of seronegative women and may be transmitted to the fetus in up to 40% of cases. Up to 10% of intrauterine CMV infections result in symptomatic congenital disease at birth. Half of these children and 13% of those born with asymptomatic infection will develop significant clinical sequelae in infancy, especially sensorineural hearing loss. Routine CMV screening during pregnancy is not recommended in Spain owing to the absence of an effective CMV vaccine, the lack of preventive measures or therapy during pregnancy, the difficulty in diagnosing a reactivated infection, and the possibility of symptomatic congenital infections in children of immune women. However, sensitive and specific methods to diagnose primary maternal and fetal infection now exist, and new preventive and therapeutic measures have been developed. Currently, these procedures are not universally available and need to be tested in larger trials. Furthermore, the prevalence of seropositive status in pregnant women, the frequency of congenital infection, and the percentage of infants born with hearing impairment and mental retardation in our country are not known. Therefore, it would not be appropriate to introduce routine screening for CMV in pregnancy at the present time. However, increased efforts should be made to inform women about congenital CMV disease, to develop the diagnosis of fetal infection and methods to determine the extent of involvement in the case of suggestive ultrasound findings, and to treat symptomatic infected newborns with antivirals to reduce hearing impairment.

Congenital cytomegalovirus infections

Congenital cytomegalovirus (CMV) infection is one of the most common viral causes of congenital infections in high resource countries and a leading cause of hearing loss as well as an important contributor to neurodevelopmental disabilities in children. During early pregnancy, CMV has a teratogenic potential and may cause malformations such as migrational disturbances in the brain, which can be visualised using neuroimaging methods such as magnetic resonance imaging (MRI) in such children. As a consequence of variation in epidemiology and seropositivity in fertile women, the prevalence of congenital CMV in their offspring varies in different countries between 0.15-2.0%. Some 10-20% of all children with congenital CMV infections exhibit signs of neurological damage when followed up. This is the case in children both with and without symptoms of infection at birth. Until vaccines and non-toxic antiviral agents are available, hygienic measures are important as prophylaxis. Treatment with antiviral agents may have a place in children with central nervous system involvement during the neonatal period.

Recent advances in the prevention and treatment of congenital cytomegalovirus infections

Continued but slow progress has led to recent advances in our understanding that congenital cytomegalovirus (CMV) infection has occurred. We understand that the most severe congenital disease occurs following a primary maternal infection during pregnancy. We now have the ability to accurately diagnosis a primary maternal infection using serologic studies of single serum sample. For pregnant women with young children, we know that child-to-mother CMV transmission can probably be prevented by hygienic intervention, and that for pregnant women who have acquired a primary CMV infection, mother-to-fetal transmission is probably preventable using CMV hyperimmune globulin. Although additional studies are needed, treatment of congenitally infected fetuses or newborns should be possible using either CMV hyperimmune globulin or antiviral agents such as ganciclovir or its derivates. Finally, recent evidence indicates that CMV replicates in the placenta, impairs development, and causes inflammation and dysfunction. This plus the reversibility of many manifestations of congenital infection in the fetus and newborn indicate that congenital CMV disease is in part a syndrome of placental insufficiency.

Selecting neonates with congenital cytomegalovirus infection for ganciclovir therapy

OBJECTIVE

The objective of this study is to look for evidence based or scientific guidelines for selection of newborns with congenital cytomegalovirus (CMV) infection that might benefit from treatment with ganciclovir.

MATERIALS AND METHODS

A literature search was conducted involving the MEDLINE database and the Cochrane Collaboration Library. Abstracts were reviewed to select pertinent articles dealing with ganciclovir therapy in neonates. References from selected articles as well as from reviews were screened for additional relevant articles. In total, 13 case reports (16 patients in all), three descriptive uncontrolled studies (20 patients in all), two randomized dose-comparative studies (54 patients in all) and one randomized controlled study (42 patients) were identified.

OBSERVATIONS

All reported patients presented with central nervous system manifestation of CMV infection. Only the randomized controlled study showed a reduction of hearing deterioration in the treated group. Published predictors of hearing loss in congenitally CMV infected children allow identification of candidates that might benefit from treatment. Studies so far are promising but of insufficient number to make evidence based recommendations about indications for treatment of congenital CMV. As such, studies are very difficult to conduct and treatment of infants at high risk of hearing loss may appear justified. There is scientific data to help clinicians in selecting a subgroup of infants that is at higher risk of hearing deterioration and therefore might benefit the most from ganciclovir therapy.

A dose response study following in utero and lactational exposure to di-(2-ethylhexyl) phthalate (DEHP): Reproductive effects on adult male offspring rats

The reproductive effects of in utero and lactational exposure to di-(2-ethylhexyl) phthalate (DEHP) in adult male offspring rats were investigated. The selected endpoints included reproductive organ weights, testicular function, hormonal status, sexual behaviour and fertility. Two wide ranges of doses, low and high, were tested. Female Wistar rats were treated daily with DEHP and peanut oil (vehicle control) by gavage from gestation day 6 to lactation day 21. The low-doses were 0.015, 0.045, 0.135, 0.405 and 1.215 mg DEHP/kg body weight (bw)/day, and the high-doses were 5, 15, 45, 135 and 405 mg DEHP/kg bw/day. A reduction in daily sperm production of 19-25% in relation to control was observed in animals exposed to 15, 45, 135 and 405 mg/kg/day. Quantitation of specific cell types shows that the observed effects in daily sperm production are not related to changes in the number of Sertoli cells or their capability to support early stages spermatocytes. A low incidence of cryptorchidism was observed in DEHP exposed groups with a lowest observed adverse effect level of 5mg/kg/day. Serum testosterone concentration was similar to control at most doses but was significantly increased at 0.045, 0.405 and 405 mg DEHP/kg/day. In spite of this effect, the weight of seminal vesicle with coagulating glands was significantly reduced at 405 mg/kg/day. Testis, epididymis and prostate weights were similar among groups. Fertility and sexual behaviour were not affected by DEHP treatment at any dose. Overall, our results show that in utero and lactational DEHP exposure reduces daily sperm production and has the potential to induce reproductive tract abnormalities (of which cryptorchidism seems to be the most sensitive in our rat strain) in male offspring rats. The lowest observed adverse effect levels (LOAELs) for these effects were 15 and 5 mg/kg/day, respectively. Therefore, the no observed adverse effect level (NOAEL) for this study can be set at 1.215 mg/kg/day.

Effects of methyltestosterone on reproduction in the Japanese quail (Coturnix coturnix japonica)

Although the hormone-mediated effects of the synthetic androgenic hormone methyltestosterone (MT) are well characterized in mammals, little is known about endocrine and other toxic effects on reproduction in birds. In a one-generation study, MT was administered to adult Japanese quail (12 pairs per group) at dietary dose levels of 0, 10, 50, and 110 ppm for a period of 3 weeks. Reproductive performance was severely affected in the groups receiving 50 and 110 ppm MT. In females, the egg-laying rate was reduced not only related to the dose administered but also to the duration of treatment. The administration of 110 ppm, and to a lesser extent, of 50 ppm MT resulted in an immediate and dramatic decrease in the total number of eggs laid, which complicated reliable assessment of other reproduction-related parameters. In males, the findings suggested inhibition of spermatogenesis at dose levels of 50 ppm and above, resulting in a subsequent reduction in male fertility.

Anti-herpes viruses agents

Antiviral agents with demonstrated efficacy are currently available for the management of infections in children caused by the herpes viruses including herpes simples type 1 (HSV1) and type 2 (HSV2), varicella-zoster virus (VZV), and cytomegalovirus (CMV). Recently, progress has been made in the development of newer agents with enhanced activity against these viruses including resistant strains. This review focuses on the activity, clinical pharmacology, and clinical indications of antiviral agents used in the treatment of infections caused by the different herpes viruses in children.

Male reproductive toxicity and beta-luteinizing hormone gene expression in sexually mature and immature rats exposed to 2-bromopropane

1. The reproductive effects of 2-bromopropane (2-BP) in sexually mature and immature male Sprague-Dawley rats were investigated. The animals were randomly divided into three treatment groups and one control group each of which comprised six mature and six immature rats. The treated groups were injected s.c. 200, 600 and 1800 mg/kg of 2-BP on 5 days a week for 5 - 7 weeks and the control group received the vehicle. 2. The absolute and relative testis weights were significantly reduced in 600 and 1800 mg/kg b.w. dose groups in both mature and immature rats. The absolute epididymis, prostate, seminal vesicle, and pituitary weights and the relative epididymis weights, however, were significant only at the highest dose level used in both mature and immature rats. 3. The sperm concentration and sperm viability in epididymal duct decreased and the percentage of abnormal sperm increased in a dose-dependent manner in both mature and immature rats. Additionally, serum testosterone level was significantly decreased in all dose groups in mature rats, and was significantly reduced only in the group treated with the middle and highest dose in immature rats. 4. In both mature and immature rats treated with 200 and 600 mg/kg, the seminiferous tubules were atrophied and all types of germ cells were decreased in number. At the highest dose level, the effect was more marked showing severely atrophied seminiferous tubules and a complete loss of all types of germ cells. 5. The mating, pregnancy and fertility indices were significantly reduced in the 600 and 1800 mg/kg groups. Additionally, at the highest dose group the number of implantations and viable fetuses per litter were reduced and the resorption rate was increased significantly. 6. In the mature rats, the beta-LH gene expression increased significantly in the 1800 mg/kg group when compared to the control group. 7. It can be concluded that 2-BP induces alterations in both neuro-endocrine axis and the reproductive tract under the present experimental conditions. The no observed adverse effect level (NOAEL) in this study could be estimated to be lower than 200 mg/kg/b.w. based on the alteration in testicular morphology as well as on sperm parameters observed at the dose level of 200 mg/kg.

Reproductive toxicity and tissue concentrations of 3,3',4,4'-tetrachlorobiphenyl (PCB 77) in male adult rats

1 The aim of this study was to ascertain the reproductive effects of PCB 77 on adult male rats and to determine its concentration in the liver and testis. Adult male rats (n = 15/group) were treated subcutaneously with a single dose of 18 mg/kg bw (PC18) or with 60 mg/kg bw (PC60). The substance was dissolved in a 10 ml volume of peanut oil/kg. Control rats received the same volume of the vehicle. The reproductive effects as well as the concentration of PCB 77 in the liver and testis were investigated 1, 4 and 8 weeks after treatment. 2 In both groups, the daily sperm production (DSP; x10(6)) remained permanently reduced in the PC18 as well as in the PC60 groups throughout the entire investigation period (DSP week 8: control: 31 +/- 7; PC18: 22 +/- 5; PC60: 20 +/- 7). The sperm number (x10(6)) per cauda epididymis was affected only at the 1st and 4th week after treatment (control week 1: 211 +/- 67; PC18 week 1: 135 +/- 62; PC60 week 1: 142 +/- 49). Moreover, a significant increase in the percentage of abnormal sperm was observed 4 weeks following treatment in the PC18 and PC60 groups and 8 weeks after treatment in the PC60 group. Abnormal tails were the most frequent changes observed. 3 The relative testicular and prostata weights (g) were slightly increased in the PC60 group at the 1st and 4th week following treatment (testis weight: control/I: 0.46 +/- 0.02; PC60/I: 0.51 +/- 0.03). 4 The serum testosterone concentrations and effects on testis morphology were not reported. 5 The maximum concentration of PCB 77 was detected in the liver and testis 1 week after treatment. The concentration declined 4 weeks after treatment in both organs, but still a significant amount of PCB 77 was detectable in the liver as well as in the testis 8 weeks after treatment. 6 The results demonstrate that PCB 77 affects sperm variables when applied to adult rats and that the elimination of PCB 77 in the testis parallels that of the liver.