Publications by authors named "Lluis Bassas"

Study Question: Can genome-wide genotyping data be analysed using a hypothesis-driven approach to enhance the understanding of the genetic basis of severe spermatogenic failure (SPGF) in male infertility?

Summary Answer: Our findings revealed a significant association between SPGF and the gene and identified three novel genes (, , and ) along with 32 potentially pathogenic rare variants in 30 genes that contribute to this condition.

What Is Known Already: SPGF is a major cause of male infertility, often with an unknown aetiology. SPGF can be due to either multifactorial causes, including both common genetic variants in multiple genes and environmental factors, or highly damaging rare variants.

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PSA screening has led to an over-diagnosis of prostate cancer (PCa) and unnecessary biopsies of benign conditions due to its low cancer specificity. Consequently, more accurate, preferentially non-invasive, tests are needed. We aim to evaluate the potential of semen sEV (small extracellular vesicles) tsRNAs (tRNA-derived small RNAs) as PCa indicators.

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Despite that the SARS-CoV-2 pandemic has been controlled, it has affected a large proportion of the population, raising some concerns about potential sequelae in men at reproductive age. To contribute to the clarification of this issue, we performed a retrospective study comparing semen parameters values before and after confirmed SARS-CoV-2 infection in a large cohort of infertile men, compared to a control group that did not undergo SARS-CoV-2 infection. Wilcoxon test on paired samples and general linear regression model showed that SARS-CoV-2 infection has a detrimental effect on semen volume values ( < 0.

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Study Question: Do the genetic determinants of idiopathic severe spermatogenic failure (SPGF) differ between generations?

Summary Answer: Our data support that the genetic component of idiopathic SPGF is impacted by dynamic changes in environmental exposures over decades.

What Is Known Already: The idiopathic form of SPGF has a multifactorial etiology wherein an interaction between genetic, epigenetic, and environmental factors leads to the disease onset and progression. At the genetic level, genome-wide association studies (GWASs) allow the analysis of millions of genetic variants across the genome in a hypothesis-free manner, as a valuable tool for identifying susceptibility risk loci.

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Small RNA-sequencing (small RNA-seq) has revealed the presence of small RNA-naturally occurring variants such as microRNA (miRNA) isoforms or isomiRs. Due to their small size and the sequence similarity among miRNA isoforms, their validation by RT-qPCR is challenging. We previously identified two miR-31-5p isomiRs-the canonical and a 3'isomiR variant (3' G addition)-which were differentially expressed between individuals with azoospermia of different origin.

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Background: Non-invasive molecular biomarkers for classifying azoospermia by origin into either obstructive or non-obstructive/secretory azoospermia, as well as for inferring the spermatogenic reserve of the testis of non-obstructive/secretory azoospermia patients, are of great interest for testicular sperm retrieval outcome prediction for assisted reproduction. Prior analyses of semen small non-coding RNA expression in azoospermia have focused on microRNAs, but there has been a lack of attention on other regulatory small RNA species. In this regard, studying more in-depth expression changes of small non-coding RNA subtypes in small extracellular vesicles from semen of azoospermic individuals could be useful to select additional non-invasive biomarkers with diagnostic/prognostic purposes.

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Reproductive dysfunction and urogenital malignancies represent a serious health concern in men. This is in part as a result of the absence of reliable non-invasive tests of diagnosis/prognosis. Optimizing diagnosis and predicting the patient's prognosis will affect the choice of the most appropriate treatment and therefore increase the chances of success and the result of therapy, that is, it will lead to a more personalized treatment of the patient.

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Article Synopsis
  • - Severe spermatogenic failure (SPGF) is a major cause of male infertility, leading to conditions like severe oligozoospermia (SO) and non-obstructive azoospermia (NOA), with most cases being of unknown origin.
  • - This study investigated whether certain genetic variations in a gene related to spermatogenesis contribute to the risk of idiopathic SPGF, examining 727 SPGF cases and 1,058 unaffected men from the Iberian Peninsula.
  • - Findings indicated a significant association between the minor allele frequency of a specific SNP and SO, suggesting that these genetic variations may affect spermatogenesis by altering the binding of key transcription factors, reinforcing the complexity of idiopathic SPGF.
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We conducted a genome-wide association study in a large population of infertile men due to unexplained spermatogenic failure (SPGF). More than seven million genetic variants were analysed in 1,274 SPGF cases and 1,951 unaffected controls from two independent European cohorts. Two genomic regions were associated with the most severe histological pattern of SPGF, defined by Sertoli cell-only (SCO) phenotype, namely the MHC class II gene HLA-DRB1 (rs1136759, P = 1.

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Article Synopsis
  • Biomedical science is improving in transparency and reproducibility, which is crucial for research involving semen analysis.
  • Two key documents have been released: the WHO Laboratory Manual and the International Standard ISO 23162:2021, both focusing on semen examination protocols.
  • It is recommended that authors adhere to these guidelines when publishing their studies, ideally using a provided checklist for proper compliance.
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(1) Background: Obesity is associated with hypogonadism, sexual dysfunction, and impaired fertility in men. However, its effects on semen parameters or sexual function remain debatable. (2) Methods: This paper involves a longitudinal study in men submitted for obesity surgery at a university tertiary hospital.

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Background And Objectives: Predicting the origin of azoospermia with non-invasive biomarkers is clinically relevant for determining the chance of successful sperm retrieval from the testes before attempting assisted reproduction treatment. Here, the semen small extracellular vesicle microRNA miR-31-5p-based biomarker test to distinguish obstructive azoospermia from secretory azoospermia (previously described by our group) is validated for clinical use, and additionally, the sample source (seminal small extracellular vesicles vs. total seminal plasma) as a preanalytical variable is considered to optimize the procedure.

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Background: Previous studies in animal models evidenced that genetic mutations of KATNAL1, resulting in dysfunction of its encoded protein, lead to male infertility through disruption of microtubule remodelling and premature germ cell exfoliation. Subsequent studies in humans also suggested a possible role of KATNAL1 single-nucleotide polymorphisms in the development of male infertility as a consequence of severe spermatogenic failure.

Objectives: The main objective of the present study is to evaluate the effect of the common genetic variation of KATNAL1 in a large and phenotypically well-characterised cohort of infertile men because of severe spermatogenic failure.

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We aimed to analyze the role of the common genetic variants located in the locus, a relevant prolyl isomerase required to control the proliferation of spermatogonial stem cells and the integrity of the blood-testis barrier, in the genetic risk of developing male infertility due to a severe spermatogenic failure (SPGF). Genotyping was performed using TaqMan genotyping assays for three taggers (rs2287839, rs2233678 and rs62105751). The study cohort included 715 males diagnosed with SPGF and classified as suffering from non-obstructive azoospermia (NOA, = 505) or severe oligospermia (SO, = 210), and 1058 controls from the Iberian Peninsula.

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Article Synopsis
  • The research investigates whether genome-wide genotyping can help identify the genetic causes behind total globozoospermia in two brothers from a non-consanguineous family.
  • The study involved clinical assessments, sperm analysis, and molecular testing to explore the presence of genetic mutations, particularly focusing on the DPY19L2 gene.
  • The findings suggest that using a genome-wide analysis can be valuable for understanding globozoospermia and other rare genetic conditions, especially in families without a history of genetic issues.
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Objective: To describe the epidemiological, clinical and laboratory characteristics of male patients diagnosed with Haemophilus spp. urethral infection and to compare them with the characteristics of male patients diagnosed with N. gonorrhoeae, C.

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Background: Severe spermatogenic failure (SpF) represents the most extreme manifestation of male infertility, as it decreases drastically the semen quality leading to either severe oligospermia (SO, <5 million spermatozoa/mL semen) or non-obstructive azoospermia (NOA, complete lack of spermatozoa in the ejaculate without obstructive causes).

Objectives: The main objective of the present study is to analyze in the Iberian population the effect of 6 single-nucleotide polymorphisms (SNPs) previously associated with NOA in Han Chinese through genome-wide association studies (GWAS) and to establish their possible functional relevance in the development of specific SpF patterns.

Materials And Methods: We genotyped 674 Iberian infertile men (including 480 NOA and 194 SO patients) and 1058 matched unaffected controls for the GWAS-associated variants PRMT6-rs12097821, PEX10-rs2477686, CDC42BPA-rs3000811, IL17A-rs13206743, ABLIM1-rs7099208, and SOX5-rs10842262.

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Infertility is a growing concern in developed societies. Two extreme phenotypes of male infertility are non-obstructive azoospermia (NOA) and severe oligospermia (SO), which are characterized by severe spermatogenic failure (SpF). We designed a genetic association study comprising 725 Iberian infertile men as a consequence of SpF and 1058 unaffected controls to evaluate whether five single-nucleotide polymorphisms (SNPs), previously associated with reduced fertility in Hutterites, are also involved in the genetic susceptibility to idiopathic SpF and specific clinical entities.

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Seminal plasma (SP) contains a unique concentration of miRNA, mostly contained in small extracellular vesicles (sEVs) such as exosomes, some of which could be clinically useful for diagnosis and/or prognosis of urogenital diseases such as prostate cancer (PCa). We optimized several exosome-EV isolation technologies for their use in semen, evaluating EV purifying effectiveness and impact on the downstream analysis of miRNAs against results from the standard ultracentrifugation (UC) method to implement the use of SP sEV_miRNAs as noninvasive biomarkers for PCa. Our results evidenced that commercial kits designed to isolate exosomes/EVs from blood or urine are mostly applicable to SP, but showed quantitative and qualitative variability between them.

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Article Synopsis
  • The study investigates the link between variations in the SOHLH2 gene and male infertility, focusing on severe oligospermia and nonobstructive azoospermia.
  • Evidence was found that specific genetic polymorphisms (rs6563386 and rs1328626) are associated with sperm production issues, with a dominant effect suggested for minor alleles.
  • The research concludes that intronic variations in SOHLH2 likely contribute to spermatogenic failure, influenced by different combinations of these genetic variants.
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There is an urgent need for accurate non-invasive biomarkers for prostate cancer (PCa) diagnosis and disease risk stratification. Previous data suggests that total seminal plasma (SP) represents a source of miRNAs for screening. We have evaluated a panel of eight PCa-associated miRNAs for their potential use as PCa biomarkers in SP by analyzing their levels using RT-qPCR.

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Background: The exact mechanism of varicocele-related infertility is still elusive, therefore, the current challenges for its management lie in determining which patients stand to benefit most from surgical correction. The authors aimed to assess the clinical factors affecting semen improvement after left microsurgical subinguinal varicocelectomy (MSV) in relation to patient age, ultrasound varicocele grading (USVG), and presence of a right subclinical varicocele (RSV).

Methods: From 2010 to 2017 a total of 228 infertile patients underwent left MSV for clinical varicocele.

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Although it is specific for prostatic tissue, serum prostate-specific antigen (PSA) screening has resulted in an over-diagnosis of prostate cancer (PCa) and many unnecessary biopsies of benign disease due to a well-documented low cancer specificity, thus improvement is required. We profiled the expression level of miRNAs contained in semen exosomes from men with moderately increased PSA levels to assess their usefulness, either alone or in addition to PSA marker, as non-invasive biomarkers, for the early efficient diagnosis and prognosis of PCa. An altered miRNA expression pattern was found by a high throughput profiling analysis in PCa when compared with healthy individuals (HCt) exosomal semen samples.

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Study Question: Are exosomal microRNAs (miRNAs) in seminal plasma (SP) useful as markers of the origin of azoospermia and the presence of sperm in the testis?

Summary Answer: Our study demonstrated the potential of several miRNAs contained in small extracellular vesicles (sEVs) of seminal fluid as sensitive and specific biomarkers for selecting those azoospermic individuals with real chances of obtaining spermatozoa from the testicular biopsy.

What Is Known Already: There are no precise non-invasive diagnostic methods for classifying the origin of the sperm defects in semen and the spermatogenic reserve of the testis in those infertile men with a total absence of sperm in the ejaculate (azoospermia). The diagnosis of such individuals is often based on the practice of biopsies.

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