Littérature scientifique sur le sujet « Non-obstructive azoospermia »

Azoospermia may occur because of reproductive tract obstruction (obstructive azoospermia) or inadequate production of spermatozoa, such that spermatozoa do not appear in the ejaculate (non-obstructive azoospermia). Azoospermia is diagnosed based on the absence of spermatozoa after centrifugation of complete semen specimens using microscopic analysis. History and physical examination and hormonal analysis (FSH, testosterone) are undertaken to define the cause of azoospermia. Together, these factors provide a >90% prediction of the type of azoospermia (obstructive v. non-obstructive). Full definition of the type of azoospermia is provided based on diagnostic testicular biopsy. Obstructive azoospermia may be congenital (congenital absence of the vas deferens, idiopathic epididymal obstruction) or acquired (from infections, vasectomy, or other iatrogenic injuries to the male reproductive tract). Couples in whom the man has congenital reproductive tract obstruction should have cystic fibrosis (CF) gene mutation analysis for the female partner because of the high risk of the male being a CF carrier. Patients with acquired obstruction of the male reproductive tract may be treated using microsurgical reconstruction or transurethral resection of the ejaculatory ducts, depending on the level of obstruction. Alternatively, sperm retrieval with assisted reproduction may be used to effect pregnancies, with success rates of 25–65% reported by different centres. Non-obstructive azoospermia may be treated by defining the cause of low sperm production and initiating treatment. Genetic evaluation with Y-chromosome microdeletion analysis and karyotype testing provides prognostic information in these men. For men who have had any factors potentially affecting sperm production treated and remain azoospermic, sperm retrieval from the testis may be effective in 30–70% of cases. Once sperm are found, pregnancy rates of 20–50% may be obtained at different centres with in vitro fertilisation and intracytoplasmic sperm injection.

Background: Azoospermia is a highly upcoming subject in the last few decades. In the past, use of donor sperm was the only option providing a realistic chance of conception for couples affected by azoospermia. Introduction of sperm retrieval techniques and assisted reproductive technologies, especially intracytoplasmic sperm injection (ICSI), has provided these men a chance to father their genetically own child and changed the management approach significantly. The aim of this study was to compare the outcome of intracytoplasmic sperm injection (ICSI) of surgically retrieve sperms between couples with infertility due to male non-obstructive azoospermia (NOA) and obstructive azoospermia (OA).Methods: It was a retrospective observational study and data analysis was conducted at Centre for Infertility and Assisted Reproduction (CIMAR), Edappal, Kerala, India from January 2018 to December 2021. The selection of cases was based on detailed history, physical examination, husband’s semen analysis confirmed twice and hormone profile. During a period of four years, 754 azoospermic patients were diagnosed at our centre. In this study, female age <35 years considered as the inclusion criteria as female age plays a pivotal role for IVF/ICSI outcome, while patient in whom voluntary donor sperm used, patients in whom sperm retrieval failed, female age >35 years and female associated with any pathology which can alter the treatment outcome e.g., endometriosis, severe adenomyosis, diminished ovarian reserve, fibroid uterus were excluded from the study groups. On the basis of serum FSH, serum testosterone and testicular size and considering inclusion and exclusion criteria, patients were subdivided into two group as: group A (n=75) included patients with non-obstructive azoospermia and group B (n=75) included patients with obstructive azoospermia, underwent ICSI.Results: Clinical pregnancy rate, fertilization and implantation rate were found to be higher in OA cases in comparison to those of NOA cases. Grade A embryo formation rate and miscarriage rate showed no significant difference.Conclusions: As the cause of azoospermia is different in both the groups, the chances of achieving a successful outcome (fertilization rate, embryo formation rate, and clinical pregnancy rate) after ICSI are negatively affected by the type of azoospermia and are reduced in men with NOA in comparison to patients with OA.

Introduction: The aim of our research was to establish the relevance of testicular histopathology on sperm retrieval after testicular sperm extraction in patients with non-obstructive azoospermia and in patients with obstructive azoospermia, who already underwent a previous failure testicular fine needle aspiration. Methods: We evaluated a total of 82 azoospermic men, underwent testicular sperm extraction, referring to the Assisted Reproductive Technology Centre of the University of Florence, Italy between January 2008 and March 2017. A general and genital physical examination, scrotal and trans-rectal ultrasound, semen analysis, hormone measurements, including follicle-stimulating hormone, luteinizing hormone and total testosterone, were collected. Results: Successful sperm retrieval was obtained in 36 men of total (43.9%). Successful sperm retrieval was 29.5% in non-obstructive azoospermia patients, while men with obstructive azoospermia, who, underwent a previous failure testicular fine needle aspiration, had sperm retrieval in 86% of cases. Mean luteinizing hormone was 6.55 IU/L, total testosterone 4.70 ng/mL, right testicular volume 13.7 mL and left testicular volume 13.6 mL. Mean Follicle-stimulating hormone was 13.45 IU/L in patients with negative sperm retrieval and 8.18 IU/L in men with successful sperm retrieval. According to histology, 20.7% had normal spermatogenesis, 35.3% hypospermatogenesis, 35.3% maturation arrest and 8.5% Sertoli cell-only syndrome. Successful sperm retrieval was 88.2% in patients with normal spermatogenesis, 24.1% in the maturation arrest group and 48.27% in patients with hypospermatogenesis, while negative sperm retrieval was reported in Sertoli cell-only syndrome patients. Seven cases with maturation arrest showed a successful sperm retrieval. Conclusion: Testicular histopathology after testicular sperm extraction offers important information on prediction of sperm retrieval and can guide the surgeon in choosing the more suitable therapeutic practice.

Over the past 20 years, there has been a clear trend to increase in the number of infertile men in Ukraine, their percentage reaches 50% in infertile couples. There is a significant percentage of male infertility caused by azoospermia – the lack of sperm in the ejaculate. In male infertility, azoospermia is found in 10–15% of patients, among other forms of pathospermia. Given the ambiguity of ideas about the etiology, pathogenesis and treatment and diagnostic approaches for various types of infertility, it remains important to clarify the relationship of urogenital infections with the regulatory systems of cells, including the state of the pro- and antioxidant system and the search for additional markers. 119 patients with various forms of azoospermia were examined. All patients underwent the following studies: spermogram, infectious screening, inhibin B, lipid peroxidation, activity of enzymes of the glutathione antioxidant system in sperm plasma and blood serum. Infectious screening included analysis of urethral secretions, bacteriological examination of sperm or prostate secretion, assessment of the species and quantitative composition of the microflora of the male urogenital tract. According to the results of spermogram and other diagnostic methods, a non-obstructive form of azoospermia was detected in 69 patients. In obstructive azoospermia, ejaculate as such was absent. It is suggested that inhibin B may be an important medical diagnostic test for azoospermia. As a result of the conducted researches the importance of determining the concentration of inhibin B as a marker of azoospermia was demonstrated and a negative correlation of moderate strength between the content of inhibin B and testosterone level in the plasma of men with non-obstructive azoospermia was revealed. It was found that Ureaplasma pervum and Ureaplasma urealyticum infect the male genitourinary system to the greatest extent among a number of microorganisms, both in non-obstructive and obstructive forms of azoospermia. Enterococcus faecalis is more pronounced in the sperm fluid in the non-obstructive form of azoospermia and prostate secreton in the obstructive form of azoospermia. In the non-obstructive form of azoospermia in the seminal plasma and serum, the processes of lipid peroxidation intensify, the concentration of reduced glutathione decreases and the activities of the enzymes of the glutathione antioxidant system (glutathione peroxidase and glutathione transferase) decrease. It can be considered that an important diagnostic test for the nonobstructive form of azoospermia is the ratio of reduced glutathione to oxidized glutathione in sperm plasma.

Azoospermia is divided into two categories of obstructive azoospermia and non-obstructive azoospermia. Before 1995, couples with a male partner diagnosed with non-obstructive azoospermia had to choose sperm donation or adoption to have a child. Currently, testicular sperm aspiration or micro-dissection testicular sperm extraction combined with intracytoplasmic sperm injection allows patients with non-obstructive azoospermia to have biological offspring. The sperm retrieval rate is significantly higher in micro-dissection testicular sperm extraction compared with testicular sperm aspiration. Additionally, micro-dissection testicular sperm extraction has the advantages of minimal invasion, safety, limited disruption of testicular function, a low risk of postoperative intratesticular bleeding, and low serum testosterone concentrations. Failed micro-dissection testicular sperm extraction has significant emotional and financial implications on the involved couples. Testicular sperm aspiration and micro-dissection testicular sperm extraction have the possibility of failure. Therefore, predicting the sperm retrieval rate before surgery is important. This narrative review summarizes the existing data on testicular sperm aspiration and micro-dissection testicular sperm extraction to identify the possible factor(s) that can predict the presence of sperm to guide clinical practice. The predictors of surgical sperm retrieval in patients with non-obstructive azoospermia have been widely studied, but there is no consensus.

Background: EIF1AY is one of the genes essential for normal spermatogenesis and is located in azoospermic factors region. Objective: The present study was designed to investigate the EIF1AY gene nucleotide variations, and correlate it with spermatogenic maturation arrest and azoospermia in Iranian population. Methods: A total number of 30 Iranian idiopathic non-obstructive azoospermic patients were selected as case group and 30 fertile men served as a control group who had at least 1 child. Nucleotide variation was analyzed in exon 3 and exon 5 in EIF1AY gene of both groups. DNA extraction from peripheral blood samples of selected individuals was done followed by amplification by PCR and sequencing with Sangar method. Results: Totally 3 single nucleotide variations were identified: one in the intronic region of exon 3, next one in non-coding transcript exon variant (rs13447352) and the third one in the exonic region of exon 5, all were registered in NCBI-Gene database. Conclusion: There was no statistically significant difference in the incidence of nucleotide variation between 2 study populations (p > 0.05). Further studies are required to specify the effects of Y: T20588295G variation on modification of protein structure, as well as the expression pattern of the gene and its association with azoospermia.

Parmi les couples avec un projet parental, le facteur masculin d’infertilité est responsable d’environ 20%. Malgré de longues années d’activités d’assistance médicale à la procréation, un nombre important de cas reste idiopathiques. Considérant le nombre élevé des gènes potentiellement impliqués dans la gamétogenèse, il est fort probable que la majorité des formes ‘idiopathiques’ sont d’origine génétique. Dans l'étude présente, nous avons d’identifier deux nouveaux gènes impliqués dans une infertilité masculine. Nos données suggèrent que la mutation dans TEX15 puisse corréler avec une diminution du nombre de spermatozoïdes au fil du temps. Un test diagnostique identifiant la mutation chez un patient pourrait fournir une indication d’organiser au plus tôt une cryopréservation du sperme. On a aussi identifié MAGEB4 liées à l’X comme un nouveau gène impliqué dans une infertilité masculine héritée. Cette étude fournit le premier indice sur la fonction physiologique d'une protéine MAGE
Among couples with a desire for a child, male factor is responsible approximately 20%. Despite long years of assisted reproductive activities, a significant number of cases remain idiopathic. Considering the high predicted number of genes involved in male gametogenesis, it is likely that most ‘idiopathic’ forms may have a genetic origin. In the present study, we have defined two new genes implicated in male infertility. Our data suggested that a nonsense mutation in TEX15 correlates with a decrease in sperm count over time. A diagnostic test identifying the mutation in man could provide an indication of spermatogenic failure and prompt patients to undertake sperm cryopreservation at an early age. We also identified MAGEB4 as a new X-linked gene involved in an inherited male infertility. This study provides the first clue on the physiological function of a MAGE protein

ABSTRACT The severest form of male factor infertility is non-obstructive azoospermia (NOA), which occurs in approximately 1% of all men in reproductive age. It is common knowledge that Klinefelter Syndrome (47, XXY) and Y-chromosome microdeletions are direct causes of NOA, but in the majority of patients the etiology of this spermatogenic alteration is still unknown. The global aim of the present thesis was to enhance our understanding on genetic factors involved in non-obstructive azoospermia. The first part of the thesis focuses on the search of X-linked “AZF-like” regions. The Y-linked AZF deletions, which arise through Non-Allelic Homologous Recombination (NAHR), are the first example in andrology of functionally relevant Copy Number Variations (CNVs) causing spermatogenic failure. In analogy to the Y chromosome, the X chromosome is enriched in genes involved in spermatogenesis and its hemizygous state in males implies a direct effect of a damaging deletion making it a promising target for the discovery of new genetic factors leading to male infertility. To this purpose, we performed a multi-step bioinformatic analysis starting from all X-linked CNVs reported in UCSC Genome Browser in order to select X-linked recurrent CNVs: i) flanked by segmental duplications (SDs) and thus possibly generated by the NAHR ii) containing genes that are probably under negative selection i.e. with an inverted ratio of deletions/duplications. Following the above analysis we identified 12 X-linked CNVs (candidate “AZF-like” regions) of which 10 CNVs contained genes with a predicted role during spermatogenesis. Screening for deletions was performed in 82 idiopathic NOA patients with different testis phenotypes from pure Sertoli Cell Only Syndrome (SCOS) to partial spermatid arrest. The analysis revealed a single deletion in a patient affected by pure spermatocytic arrest removing part of the members of the Opsin gene family and possibly affecting the expression of a testis specific gene, TEX28. qPCR analysis revealed that the Opsin gene family is not expressed in germ cells and the analysis of the carrier’ testis biopsy did not reveal any impairment of TEX28 expression. Therefore, no cause-effect relationship between deletion and the testis phenotype can be established. We hypothesize that the lack of deletions in our NOA cohort may be partially due to the strictly selected testicular phenotype. Hence, we cannot exclude deletions in these regions may cause a less severe impairment of spermatogenesis. On the other hand, for the regions containing ubiquitously expressed genes, the removal of one or more of these genes may cause a more complex phenotype. Our is the first study that, through a multi-step bioinformatic analysis, provides information about potential X-linked “AZF-like” regions and represents a starting point for future large scale investigations involving patients with crypto-or oligozoospermia. The second part of the thesis focuses on the sequencing of >160.000 coding exons in NOA patients and proven normozoospermic fertile controls. We performed a Whole Exome Sequencig (WES) in a set of 18 men affected by SCOS, Spermatogenic Arrest (SGA) and normozoospermic fertile controls. We studied patients with consanguineous parents and sporadic azoospermic cases. We have identified more than 22,000 variants/subject in the exons and splice sites. Concerning patients with consanguineous parents we adopted the recessive model by selecting rare (MAF≤0.01), predicted as pathogenic, homozygous variants in genes with a putative role during early spermatogenic stages. This analytic approach allowed the identification of 3 candidate genes for male infertility: FANCA, ADAD2 and MRO. The most relevant finding concerns the patient who carried the mutation p.Arg880Gln in the FANCA gene (a functionally damaging mutation) since it is the first time that Fanconi Anemia (FA) is diagnosed following an exome analysis for idiopathic NOA. Interestingly enough, the patient’s brother, also affected by NOA, was homozygous carrier of the same mutation. Although the two brothers were not aware about having Fanconi anemia, the discovery of this genetic anomaly prompted us to perform the chromosome breakage test, through which a mosaic FA was diagnosed in both subjects. Therefore, besides diagnosing the cause of NOA, we made an important incidental finding of Fanconi Anemia (chromosome instability/cancer-prone condition), providing benefit to the siblings’ future health by allowing preventive measures. For patients with unrelated parents we applied four models: i) search for hemyzigous rare X-linked pathogenic mutations (MAF≤0.01); ii) oligogenic inheritance of low-frequency/rare mutations in genes with a putative role during early spermatogenic stages; iii) synergistic effect of genes containing low-frequency/rare mutations belonging to the same biological pathway; iv) combined effect of validated genetic risk factors for NOA (common SNPs). Finally, we also performed a high resolution X-chromosome array-CGH in sporadic patients in order to complete WES data. The first model allowed us to indentify RBBP7 as a novel X-linked candidate gene for early spermatogenic stages. So far RBBP7 has been only proposed as a key regulator during oocyte meiosis, but the expression analysis performed in our laboratory in different testis biopsies showed that the encoded protein is also overexpressed in the spermatogonial cells. Concerning the X-chromosome specific array-CGH we could not identify any relevant X-linked CNV. The second model (oligogenic inheritance) allowed the identification of three patients with single heterozygous variants and three controls with multiple heterozygous mutations. Since no patients presented more than one mutation we exclude the possibility that the azoospermic phenotype is due to digenic/oligogenic inheritance. The fact that more than one mutation in these genes has been found in three normozoospermic men suggests that it is an unlikely model for NOA. Regarding the third model (Synergistic effect of multiple low frequency mutations), the enrichment analysis in NOA patients allowed the identification of an overrepresentation of genes belonging to 19 KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways. After filtering out the pathways enriched in the control group, we could define enrichment in the “regulation of actin cytoskeleton” pathway as a candidate for impaired spermatogenesis. One patient presented multiple mutations in genes forming part of this pathway suggesting a potential pathogenic mechanism for the NOA phenotype. Concerning the disease enrichment analysis we identified an overrepresentation of genes associated with neoplasms, urogenital neoplasms and Fanconi anemia/syndrome in the patient group and not in the control group. Finally, regarding the combined effect of validated genetic risk factors (common SNPs) reported in previous GWAS we did not observe differences between patients and controls. The work presented in this thesis provides further advancement in the understanding of the genomic basis of idiopathic NOA. On one hand, our bioinformatic analysis identified 12 AZF-like regions along the X-chromosome that are candidates for further large scale screening in less severe forms of male infertility. Our WES experiments proved that this approach is able to identify novel candidate genes and to provide a genetic diagnosis in patients with consanguineous parents (FANCA mutation). We provided a clear example on how WES might lead to important incidental findings and thus to diagnose a chromosome instability/cancer-prone condition with implication on general health and disease prevention. Concerning the sporadic cases, WES allowed the identification of a novel X-linked candidate gene for impaired spermatogenesis indicating that the X-chromosome remains a highly interesting target.

碩士
台北醫學院
醫學研究所
88
Abstract Testicular spermatozoa extraction from non-obstructive azoospermic (NOA) patients followed by microinjection is an effective method in the treatment of male infertility. In this study, we tried to find new parameters to predict the spermatogenesis in men with defective spermatogenesis. We conducted a prospective study of a set of variables in 37 NOA patients. The most frequently available parameters for current clinical decision-making in azoospermic patients: (i) testis size; (ii) serum concentration of follicle stimulating hormone (FSH); and (iii) presence of spermatids in the testicular biopsy histology. Applying fluorescence in situ hybridization (FISH) on testis sections to identify testicular spermatids shows higher relation to these three current predictive factors. The spermatogenesis in individual seminiferous tubule also can be examined directly. There is a significantly difference between the tubular widthes of obstructive and non-obstructive azoospermic patients. The large number of intratubular germ cells within those tubules with active spermatogenesis cause those tubules to be larger than tubules without sperm production. Our study shows that besides those conventional parameters, the combination of both applying FISH on testicular sections and microdissecting ‘fat’ seminiferous tubules can improve the probability of successful testicular sperm extraction from patients with NOA. Key words : non-obstructive azoospermia, spermatogenesis, fluorescence in situ hybridization.

Surgical sperm retrieval combined with the advent of in vitro fertilization and intracytoplasmic sperm injection has enabled many men with obstructive and non-obstructive azoospermia to father their own biological children. Several sperm retrieval techniques have been described to obtain sperm from the vas deferens, epididymis, and testicular parenchyma for use in assisted reproduction technologies. The current techniques have variable success rates but have not been subjected to randomized control trials hence the paucity of good evidence to inform the choice of one technique over the others. In experienced hands, sufficient and good quality sperm can usually be harvested for treatment and/or cryopreservation. This chapter summarizes the current techniques of surgical sperm retrieval, sperm retrieval success rate, and the role of adjuvant therapies in increasing chance of successful sperm retrieval.

The small size of microfabricated structures are opening new avenues in the field of biomedical engineering where structures are being developed to process [1] and analyze [2,3] nanolitre quantities of biological fluids, and cellular tissues. This paper outlines the design and manufacture principals of a passive micro-mechatronic device for the filtration and sorting of spermatogenic cells. This device is to be applied in a urological clinical environment where it can be used to semi-automate the spermatozoa selection process from non-obstructive azoospermic testis biopsies. Detailed and discussed herein are the advantages and drawbacks of Micro-Electro-Mechanical Systems (MEMS) as applied to clinical biomedical situations, and requirements for the design methodology and process of a microfluidic system based on MEMS technology with a view to manufacture by Deep Reactive Ion Etching process. The modelling of the micro device using computational fluid dynamic simulation methods is also covered in this paper.