Conservation du tissu testiculaire chez le garçon pré-pubère dans le champ du cancer : Impact de la congélation et du traitement reçu sur la qualité du tissu

Chez le garçon pré-pubère atteint d’un cancer, l’infertilité provoquée par les traitements a longtemps été sous-estimée. Le prélèvement chirurgical de tissu testiculaire et sa congélation constitue une des procédures possibles pour préserver leur fertilité. Cette étude a eu pour but de déterminer l’impact, d’une part, de la congélation sur la qualité structurelle du tissu testiculaire après décongélation et d’autre part, des traitements du cancer reçus préalablement à la congélation sur le nombre de spermatogonies présentes dans les tubes séminifères. Matériels et méthodes. La population de notre étude se composait de garçons âgés entre 1 an et 16 ans atteints d’un cancer consultant pour préservation de la fertilité avant conditionnement pour une allogreffe ou autogreffe de cellules souches hématopoïétiques. Une analyse histologique a été réalisée sur les biopsies testiculaires obtenues. Des marqueurs immunohistologiques ont été utilisés pour évaluer le nombre de spermatogonies (MAGE-A4) et leur capacité proliférative (PCNA). Les modifications histologiques induites par la congélation, les pathologies ou les traitements associés ont été évaluées. Résultats. Au total, 91 patients ont été inclus dans l’étude. Les scores de qualité tissulaire augmentent après décongélation (p Conclusion. La congélation lente contrôlée sans seeding permet une bonne conservation de l’architecture du tissu testiculaire tout en préservant le nombre de spermatogonies par tube séminifère. Les agents alkylants ont un effet néfaste systématique sur les spermatogonies. Il semblerait souhaitable de proposer, chez le garçon pré-pubère, la conservation de tissu testiculaire dès que le protocole de chimiothérapie envisagé inclut des agents alkylants avec une Cyclophosphamide Equivalent Dose > 4000 mg/m2

Exposure to Chemotherapy During Childhood or Adulthood and Consequences on Spermatogenesis and Male Fertility

International audienceOver the last decade, the number of cancer survivors has increased thanks to progress in diagnosis and treatment. Cancer treatments are often accompanied by adverse side effects depending on the age of the patient, the type of cancer, the treatment regimen, and the doses. The testicular tissue is very sensitive to chemotherapy and radiotherapy. This review will summarize the epidemiological and experimental data concerning the consequences of exposure to chemotherapy during the prepubertal period or adulthood on spermatogenic progression, sperm production, sperm nuclear quality, and the health of the offspring. Studies concerning the gonadotoxicity of anticancer drugs in adult survivors of childhood cancer are still limited compared with those concerning the effects of chemotherapy exposure during adulthood. In humans, it is difficult to evaluate exactly the toxicity of chemotherapeutic agents because cancer treatments often combine chemotherapy and radiotherapy. Thus, it is important to undertake experimental studies in animal models in order to define the mechanism involved in the drug gonadotoxicity and to assess the effects of their administration alone or in combination on immature and mature testis. These data will help to better inform cancer patients after recovery about the risks of chemotherapy for their future fertility and to propose fertility preservation options

Fertility Preservation in Klinefelter Syndrome Patients during the Transition Period.

International audienceSpermatozoa have occasionally been identified in ejaculate of adult Klinefelter syndrome (KS) patients but very exceptionally in KS adolescents. Spermatozoa can also be retrieved in testicular tissue of KS adolescents. The testis may also harbor spermatogonia and noncompletely differentiated germ cells. Neither clinical features nor hormonal parameters could predict germ cell recovery in KS adults or adolescents. No predictive factors can actually demonstrate that early diagnosis of KS would allow increasing the chance of sperm retrieval even if it has been suggested that semen quality may decline with age in KS patients. Leydig cell dysfunction may also be another factor that might affect the spermatogenesis process in XXY adolescents. Fertility preservation might be preferentially proposed in KS adolescents when semen sampling is possible, when the patient is able to consider alternative options to become a father, and to accept germ cell retrieval failure. However, precocious diagnosis of KS has also to be considered because it might not solely improve the possibility of fertility preservation after the onset of puberty, but also the medical care and the quality of life of these patients

Paradoxical risk of reduced fertility after exposure of prepubertal mice to vincristine or cyclophosphamide at low gonadotoxic doses in humans

Abstract Cancer treatment can have long-term side effects in cured patients and infertility is one of them. Given the urgency of diagnosis in children with cancer, the toxicity of treatments on the gonad was overshadowed for a long time. In the present study, prepubertal mice were treated by vincristine or cyclophosphamide commonly used in acute leukaemia treatment. The prepubertal exposure to cyclophosphamide, at a low gonadotoxic dose in humans (< 3.5 g/m 2 ), led to morphological alterations of prepubertal testicular tissue. An increased proportion of spermatozoa with hypocondensed chromatin and oxidized DNA associated with decreased fertility were uncovered at adulthood. Short- and long-term morphological alterations of the testicular tissue, disturbed progression of spermatogenesis along with increased proportions of isolated flagella and spermatozoa with fragmented DNA were evidenced in vincristine-treated mice. Moreover, the fertility of mice exposed to vincristine was severely affected despite being considered low-risk for fertility in humans. Paternal exposure to vincristine or cyclophosphamide before puberty had no impact on offspring development. Contrary to the current gonadotoxic risk classification, our results using a mouse model show that vincristine and cyclophosphamide (< 3.5 g/m 2 ) present a high gonadotoxic risk when administered before the initiation of spermatogenesis

Dynamics of epigenetic modifications in ICSI embryos from in vitro‐produced spermatozoa

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Vitamin E but Not GSH Decreases Reactive Oxygen Species Accumulation and Enhances Sperm Production during In Vitro Maturation of Frozen-Thawed Prepubertal Mouse Testicular Tissue

International audienceFreezing-thawing procedures and in vitro culture conditions are considered as a source of stress associated with increased reactive oxygen species (ROS) generation, leading to a damaged cell aerobic metabolism and consequently to oxidative stress. In the present study, we sought to investigate whether vitamin E (Vit E) or reduced glutathione (GSH) enhances sperm production by decreasing ROS accumulation during in vitro maturation of prepubertal mice testes. Testes of prepubertal mice were cryopreserved using a freezing medium supplemented or not supplemented with Vit E and were cultured after thawing. In presence of Rol alone in culture medium, frozen-thawed (F-T) testicular tissues exhibited a higher ROS accumulation than fresh tissue during in vitro culture. However, Vit E supplementation in freezing, thawing, and culture media significantly decreased cytoplasmic ROS accumulation in F-T testicular tissue during in vitro maturation when compared with F-T testicular tissue cultured in the presence of Rol alone, whereas GSH supplementation in culture medium significantly increased ROS accumulation associated with cytolysis and tissue disintegration. Vit E but not GSH promoted a better in vitro sperm production and was a suitable ROS scavenger and effective molecule to improve the yield of in vitro spermatogenesis from F-T prepubertal mice testes. The prevention of oxidative stress in the cytoplasmic compartment should be regarded as a potential strategy for improving testicular tissue viability and functionality during the freeze-thaw procedure and in vitro maturation

Achievement of complete in vitro spermatogenesis in testicular tissues from prepubertal mice exposed to mono- or polychemotherapy

International audienceThe assessment of the impact of chemotherapies on in vitro spermatogenesis in experimental models is required before considering the application of this fertility restoration strategy to prepubertal boys who received these treatments before testicular tissue cryopreservation. The present work investigated the effects of exposure of prepubertal mice to mono- (vincristine or cyclophosphamide) and polychemotherapy (a combination of vincristine and cyclophosphamide) on the first wave of in vitro spermatogenesis. When testicular tissue exposed to monochemotherapy was preserved, polychemotherapy led to severe alterations of the seminiferous epithelium and increased apoptosis in prepubertal testes prior in vitro maturation, suggesting a potential additive gonadotoxic effect. These alterations were also found in the testicular tissues of polychemotherapy-treated mice after 30 days of organotypic culture and were associated with a reduction in the germ cell/Sertoli cell ratio. The different treatments neither altered the ability of spermatogonia to differentiate in vitro into spermatozoa nor the yield of in vitro spermatogenesis. However, more spermatozoa with morphological abnormalities and fragmented DNA were produced after administration of polychemotherapy. This work therefore shows for the first time the possibility to achieve a complete in vitro spermatogenesis after an in vivo exposure of mice to a mono- or polychemotherapy before meiotic entry

Complete meiosis in rat prepubertal testicular tissue under in vitro sequential culture conditions

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