5th International Andrology Symposium
5th International Andrology Symposium
Vincent Prevot (Lille)
Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendorine Brain, UMR_S1172, Lille, France
Correspondence: Dr. Vincent Prévot, Ph.D. UMR_S1172, Lille, France
Mini-puberty—the brief, physiological re-activation of the hypothalamic–pituitary–gonadal (HPG) axis in early infancy—is a process critical for adult male and female reproduction. Work led by Prévot and colleagues defines mini-puberty as a neurodevelopmental program that determines both reproductive and cognitive functions. At its core is a molecular switch in infant GnRH (LH-RH) neurons in which microRNAs (notably the miR-200 family and miR-155) repress transcriptional repressors (e.g., ZEB1 and C/EBPβ), enabling the postnatal upregulation of GNRH1 transcription. Nitric-oxide (NO) signaling via NOS1 modulates this switch and therefore influences GnRH signaling. Perturbations—including DICER loss in GnRH neurons, trisomy-driven microRNA disequilibria in Down syndrome models, or NOS1 deficiency—distort pulsatility, a critical feature of the GnRH signal, with downstream reproductive and cognitive consequences. Strikingly, pulsatile (but not continuous) GnRH delivery improves cognition and strengthens basal network connectivity in adults with Down syndrome, extending GnRH’s role from a purely reproductive hormone to a systems-level neuromodulator of cortical networks. These mechanistic insights intersect directly with andrology: mini-puberty determines androgen/INSL3 function during normal testicular descent, while absent or distorted infantile HPG dynamics are linked to abnormal genital development (micropenis) and cryptorchidism in congenital GnRH deficiency. Here, I describe the development of GnRH neurons, molecular biological insights into the infantile GNRH1 transcriptional switch, evidence for extra-hypothalamic GnRH actions on cognition, and clinical implications for cryptorchidism and pediatric endocrinology. Key words Mini-puberty, GnRH neuron, Down syndrome, memory
Keywords
Mini-puberty
GnRH neuron
Down syndrome
memory
Rodolfo A. Rey
Centro de Investigaciones Endocrinológicas “Dr. César Bergadá” (CEDIE), CONICET – FEI – División de Endocrinología, Hospital de Niños Ricardo Gutiérrez, Buenos Aires, Argentina.
Correspondence: Prof.Dr. MD, PhD Rodolfo Rey Centro de Investigaciones Endocrinológicas “Dr. César Bergadá” (CEDIE), Argentina
The male hypothalamic–pituitary–testicular (HPT) axis is activated three times across the life course: during fetal life, transiently in early infancy (mini-puberty), and again with the onset of true puberty. Although both mini-puberty and puberty feature hypothalamic–pituitary activation, mini-puberty is a developmentally distinct program: Leydig cells secrete testosterone and INSL3, Sertoli cells proliferate and secrete AMH and inhibin B, but spermatogenesis does not start because Sertoli cells are physiologically androgen-insensitive in this window. The first trimester of fetal life is unique in that masculinization is pituitary independent and driven by placental hCG acting on LHCGR; by contrast, from mid-gestation onward and postnatally, pituitary control predominates. In this proceedings contribution, I synthesize cellular ontogeny (Leydig, Sertoli and germ cells), endocrine dynamics (LH/FSH, testosterone, INSL3, AMH, inhibin B), and clinical correlates (cryptorchidism, micropenis, congenital hypogonadotropic hypogonadism), integrating new molecular and single-cell insights. Mini-puberty is clinically invaluable: it offers a diagnostic window for central hypogonadism, explains phenotypic differences according to timing of androgen insufficiency, and informs management of undescended testes. Physiologic replacement strategies that mimic mini-puberty in boys with congenital hypogonadotropic hypogonadism (CHH) are emerging and appear to improve penile growth, Sertoli-cell output, and sometimes testicular descent. Finally, I frame practical implications for testing and timing of orchiopexy and articulate research priorities linking early endocrine programming to later fertility.
Keywords
Mini-puberty
fetal life
gonadotropins
Antoine H.F.M. Peters
Friedrich Miescher Institute for Biomedical Research, 4056 Basel, Switzerland; Faculty of Sciences, University of Basel, 4056 Basel, Switzerland
Correspondence; Adjunct Professor of Epigenetics, University of Basel, Basel Switzerland
Male germ cell development unfolds through a sequence of lineage transitions—primordial germ cell (PGC) specification and reprogramming, prospermatogonial (gonocyte) quiescence and conversion to spermatogonial stem cells (SSCs), amplification/differentiation of spermatogonia, and meiosis followed by spermiogenesis—that are choreographed in part by epigenetic mechanisms. DNA methylation is globally erased in PGCs and later re-established de novo in the fetal/neonatal male germ line; histone post-translational modifications (PTMs) and Polycomb-group (PcG) repressive systems create chromatin environments that both permit and restrict gene expression programs; the piRNA pathway safeguards genomic integrity by directing transposable-element silencing. Using lessons from our laboratory’s work on chromatin-based memory in gametes and early embryos, and integrating recent insights from male germ cell epigenomics, I discuss: (i) how PcG complexes (PRC1/PRC2) and their readers/writers organize developmental competence in spermatogonia; (ii) how CpG-island (CGI) methylation is protected during oogenesis by KDM2A/KDM2B to prevent aberrant maternal hypermethylation that escapes embryonic reprogramming (a paradigm for how epigenetic promoter chromatin states can be inherited); (iii) the emerging view that H3K27me3/H2AK119ub landscapes are dynamically regulated in undifferentiated spermatogonia and may be perturbed by intrinsic or environmental stressors resulting in cryptorchidism; and (iv) opportunities to apply single-cell multi-omics to cryptorchid testes to resolve whether a failed developmental transition from gonocytes to Adark SSC reflects the acquisition of intrinsic epigenetic roadblocks. I conclude by outlining a framework in which developmental “flexible repression” by Polycomb must be maintained to keep germline genes poised, while inappropriate switching to DNA-methylated locked repression at key promoters may derail fate transitions with clinical consequences for fertility.
Keywords
Epigenetic
germ cell
Polycomb group
Birgit Stallmeyer
Centre of Medical Genetics, Institute of Reproductive Genetics, University of Münster, Münster, Germany.
Correspondence: Dr. rer. nat. Birgit Stallmeyer, Centrum für Medizinische Genetik, 48149 Münster, DE
Defects in germline genome integrity and gene regulation frequently underpin male infertility. The PIWI–piRNA pathway safeguards the male germline against transposable elements (TEs) from fetal germ cells through the process of spermatogenesis. Over the past decade, particularly in recent years, exome and genome sequencing of large cohorts with clinically well-defined phenotypes has revealed that monogenic causes essentially contribute to the disease. Using data from the Münster-based MERGE cohort, we have shown that inherited defects in human piRNA biogenesis are also an important and actionable cause of spermatogenic failure. Accordingly, we have identified biallelic variants across core and accessory piRNA factors, established genotype–phenotype correlations, demonstrated loss of pachytene piRNAs in patient testis, and linked specific gene variants to transposon de-repression in human spermatogonia. Here, I summarise these recent findings and discuss the differences in the reproductive phenotypes between human variant carriers and knockout models of the mice orthologues.
Keywords
Infertility
Transposon
piRNA
Kentaro Mizuno
Department of Pediatric Urology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japa
Correspondence: Kentaro Mizuno, Nagoya City University Nagoya, Japan
Cryptorchidism disrupts the earliest transitions of male germ cells and compromises longterm fertility potential. Here I summarize our basic and clinical investigations into (i) germcelland Sertoli-cell changes in experimental and human cryptorchidism, (ii) molecular candidates involved in the differentiation process from gonocytes to spermatogonia, (iii) the timing benefit of early orchiopexy, and (iv) endocrine modifiers, including androgen signaling and neonatal thyroid status. Across rat models and pediatric cohorts, we observe delayed gonocyte resettlement to the basement membrane, reduced undifferentiated type-A spermatogonia, Sertoli-cell junctional disorganization (Claudin-11/blood-testis barrier (BTB), and transcriptional shifts implicating histone demethylation (KDM5A), FOXO1 regulation by miR-135a, and tight junction remodeling. In bilateral cryptorchidism, lower inhibin-B–to-FSH ratios track with depressed germ-cell counts at biopsy; combining AMH, inhibin B, and FSH yields strong ROC performance for predicting poor germ-cell indices, supporting pre operative endocrine triage.
Keywords
Mini-puberty
GnRH neuron
Down syndrome
memory
Jorma Toppari
Research Centre for Integrative Physiology and Pharmacology, and Centre for Population Health Research, and In Flames Research Flagship Center, Institute of Biomedicine, University of Turku, Turku, Finland, and Department of Pediatrics, Turku University Hospital, Turku, Finland
Correspondence; Prof Dr med , PhD Jorma Toppari Kiinamyllynkatu 10 20520 Turku Finland
Cryptorchidism—the failure of one or both testes to descend into the scrotum—is the most common genital anomaly in male infants and a salient risk factor for hypogonadism, impaired spermatogenesis, and testicular malignancy later in life. The neonatal hypothalamic–pituitary–testicular (HPT) axis surge (“mini-puberty”) provides a natural stress test of the infant testis, and accumulating prospective evidence shows that boys with cryptorchidism display biochemical signatures consistent with suboptimal Sertoli-cell function already in early infancy. Puberty, however, is orchestrated by a renewed activation of the HPT axis and a rapid expansion of seminiferous tubule mass; how these processes unfold in boys with a history of cryptorchidism is clinically decisive for lifetime reproductive potential. Drawing on Nordic birth cohorts from Denmark and Finland, longitudinal adolescent follow-ups, and contemporary guideline-based care, this paper synthesizes the physiology and clinical course of puberty after cryptorchidism. We summarize (i) geographic variation in cryptorchidism and the “testicular dysgenesis” paradigm; (ii) infant endocrine phenotypes that stratify later risk; (iii) trajectories of pubertal onset and tempo; (iv) testicular growth and hormone dynamics (inhibin B, AMH, FSH, LH, testosterone); (v) modifying effects of laterality, position at diagnosis, spontaneous descent versus orchiopexy, and timing of surgery; and (vi) clinical implications for counselling and follow-up. The weight of evidence indicates that pubertal timing per se is typically normal in prior cryptorchid boys, but testicular growth during puberty is blunted—most clearly in bilateral and formerly non-palpable/abdominal testes—and accompanied by lower inhibin B and modestly higher FSH (with broadly similar serum testosterone), signaling reduced Sertoli-cell mass and germ-cell output. Early orchiopexy (by 6–12 months) and spontaneous descent are associated with more favorable adolescent testicular volume and endocrine profiles than late correction. These insights refine risk stratification and motivate structured, biomarker-informed pubertal surveillance to optimize fertility counselling.
Keywords
cryptorchidism
mini puberty
Sertoli cell
treatment
Shosei Yoshida
Department of Pathology and Tumor Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
Correspondence: Prof. Yoshida Shosei PhD Higashiyama 5-1, Myodaiji, Okazaki 444-8787, Aichi, Japan
Spermatogenesis is an evolutionarily conserved but physiologically fragile process that requires the testis to operate within a tightly controlled environment. Most mammals externalize their testes into the scrotum, maintaining a cooler temperature than the abdominal cavity. Failure of testicular descent—cryptorchidism—exposes the testis to higher temperatures and may cause defects in spermatogenesis and male infertility. Yet, it has remained elusive how high temperature affects spermatogenesis, and whether heat is the sole causal factor of spermatogenic defects in cryptorchidism. A recent study from our group, using an ex vivo organ culture system, revealed that temperature elevations of only 1–2 °C induce stage-specific blocks in spermatogenesis. In particular, meiotic double-strand break repair was found to be temperature-sensitive, triggering checkpoint-mediated germ cell elimination. We also showed that heat alone does not fully explain the pathology of cryptorchid testis: While all germ cells but undifferentiated spermatogonia are depleted in an artificial cryptorchid testis model—in which testes are exposed to 38 °C—such histological features were not observed in seminiferous tubules cultured at 38 °C or any other temperature tested. Further, we found that intratesticular retinoic acid (RA) levels decline within 40–48 h following testis translocation without overt cell loss, and that exogenous RA could restore spermatogonial differentiation even under body core temperature. Together, these findings indicate that cryptorchid-associated spermatogenesis defects may result from a combined insult, with high temperature impairing meiosis and spermiogenesis, and with RA depletion compromising spermatogonial commitment. Understanding this dual mechanism will open new translational opportunities, including potential therapies targeting RA metabolism.
Keywords
Spermatogenesis
temperature adult testis
experimental cryptorchidism
Christian De Geyter
University of Basel, Switzerland,
Correspondance: Prof Dr med. em.Christian De Geyter UNI Basel Switzerland
Background: Anogenital distance (AGD) is a sexually dimorphic, life-long anthropometric marker that reflects androgen/estrogen balance during a critical fetal “masculinization programming window.” Shorter male AGD has been associated with cryptorchidism, hypospadias, impaired semen quality and reduced testicular volume—core features of the testicular dysgenesis syndrome (TDS) hypothesis. Circumstantial evidence suggests that prenatal exposure to endocrine disruptors is involved in causing TDS. Many prevalent endocrine-disrupting chemicals (EDCs) act through the estrogen receptor (ER) and can perturb fetal programming. How a transient prenatal exposure could leave durable molecular traces into adult spermatogenesis remains a key mechanistic question. A plausible mechanism is epigenetic reprogramming: in the postimplantation embryo human primordial germ cells (PGCs) undergo genome-wide DNA demethylation and subsequent re-methylation; during this window, transposable elements—particularly primate-specific Alu repeats—can be de-/re-methylated and many harbor ER-responsive sequence motifs.
Objectives: Building on clinical work from Basel we synthesize evidence and present a working model in which infertile men with shortened AGD harbor distinctive DNA-methylation patterns at estrogen-responsive Alu elements in sperm, especially within subpopulations marked by chromatin immaturity (CMA3 positivity) or apoptosis (YO-PRO-1 positivity). We outline study design, summarize core findings, and discuss translational implications and limitations.
Methods (conceptual framework): Men undergoing fertility evaluation were phenotyped (including AGD and testicular volume). Ejaculates with adequate counts were processed by swim-up and sorted by flow cytometry into fractions with high vs. low chromatin decondensation (chromomycin A3, CMA3) and with vs. without early apoptotic membrane permeability (YO-PRO-1). Reduced-representation bisulfite sequencing (RRBS) profiled CpG methylation genome-wide; bioinformatics focused on repetitive elements (Alu) containing canonical/pseudo-ERE motifs and ER-ChIP–supported sites.
Results (integrative summary): Across unsorted sperm, global CpG methylation distributions were broadly similar between infertile men (short AGD) and fertile donors. In sorted fractions, however, infertile men exhibited (i) enrichment of hypomethylated Alu-EREs within CMA3-positive and YO-PRO-1–positive sperm, and (ii) a deficit of hypermethylated Alu-EREs relative to fertile controls. These shifts were most evident in the “abnormal” subpopulations, consistent with histone retention/protamine deficiency and apoptotic signaling.
Conclusions: We propose that prenatal estrogenic/antiandrogenic perturbation (indexed in adulthood by shortened AGD) is traceable in sperm as altered methylation of ER-responsive repetitive elements. Such lesions concentrate in spermatozoa with defective chromatin maturation or incipient apoptosis, potentially contributing to reduced fertilizing competence and intergenerational epigenetic risk. We discuss how this model aligns with TDS and outline paths for validation (orthogonal epigenomics, si,ngle-cell assays, environmental exposure reconstruction).
Keywords
Cryptorchidism
ano-genital distance
estrogen
Gilvydas Verkauskas
Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
Corespondence; Prof. Dr med. Verkauskas, Head of the Centre of Children’s Surgery,
Orthopaedics and Traumatology, Vilnius University Hospital Santaros Klinikos, Vilnius,
Lithuania
Cryptorchidism affects ~2–5% of male infants at birth and ~1% at 1 year and is strongly associated with later subfertility and an increased risk of testicular cancer. Beyond mechanical maldescent, a growing body of data suggests that in a sizeable subset of boys, cryptorchidism reflects a disturbance of the hypothalamus–pituitary–gonadal (HPG) axis during fetal life and especially during mini-puberty—the postnatal surge of gonadotropins and testosterone that orchestrates Sertoli and Leydig cell maturation and the transformation of fetal gonocytes into adult dark (Ad) spermatogonia, the stem cell pool for adult spermatogenesis. This article synthesizes evidence on HPG function in cryptorchid boys, integrates prospective histology–endocrine correlations, and evaluates how timing and modality of therapy (orchiopexy alone versus combined with hormone/gonadotropin therapy) influence germ-cell outcomes and adult fertility. Drawing on published studies and the author’s clinical observations and cohort analyses, we argue that: (1) unilateral cryptorchidism often behaves as a bilateral disease at the tissue level; (2) routine serum hormones after mini-puberty have limited diagnostic power for individual risk stratification unless interpreted against histology; (3) the most consistent endocrine signal of high infertility risk is relative LH insufficiency during mini-puberty, not a primary FSH defect; (4) orchiopexy improves anatomic position but does not restore a previously abrogated minipuberty; and (5) targeted endocrine rescue—particularly GnRH/gonadotropin-based induction of mini-puberty—can normalize Ad spermatogonia formation and improve longterm semen quality in selected patients. Practical implications include earlier evaluation focused on risk stratification (not merely scheduling surgery), judicious use of testicular biopsy in expert hands, and clinical trials of mini-puberty induction guided by robust biomarkers and safety endpoints.
Darius Dasevičius
Institute for Pathology, National Centre of Pathology, Affiliate of Vilnius University Hospital Santariskiu Klinikos, 08406 Vilnius, Lithuania.
Correspondence: Dr med Darius Dasevicius Faculty of Medicine, Vilnius University, Vilnius, Lithuania
Cryptorchidism—testicular maldescent—affects 2–5% of newborn boys and ~1% at 12 months, and is linked to infertility and increased testicular germ cell tumor risk in adulthood. Histopathology provides the closest “ground truth” for prognosis, because tissue read-outs (germ cell number per tubule, presence of adult dark [Ad] spermatogonia, Sertoli-cell–only [SCO] patterns, interstitial changes) integrate upstream endocrine and paracrine events and the thermal microenvironment. This proceedings paper reviews the classical and modern histopathology of cryptorchid testes (as seen on light microscopy), highlights the methodological importance of optimized fixation and semithin resin sections for identifying Ad spermatogonia, synthesizes how biopsy metrics stratify fertility risk, and summarizes the pathology of germ cell neoplasia in situ (GCNIS) in this setting. We also integrate cohort data from Vilnius–Basel collaborations and others showing that unilateral cryptorchidism often behaves as a bilateral disease at the tissue level and that the presence or absence of Ad spermatogonia (and related indices) outperforms routine serum hormones for individual fertility prediction. Finally, we propose a practical reporting template for pediatric testicular biopsies taken at orchiopexy that preserves clinical decision-making value (fertility risk, need for endocrine induction of mini-puberty, timing of surveillance for malignancy) while respecting tissue limits and safety.
Keywords
Cryptorchidism
histology
ad spermatogonia
mini puberty
Dina Cortes
Department of Paediatrics and Adolescent Medicine, Copenhagen University Hospital Hvidovre; Department of Clinical Medicine, University of Copenhagen; in collaboration with the Department of Paediatric Surgery, Copenhagen University Hospital Rigshospitalet, Denmark.
Correspondence: Professor, overlæge, r. med. Dina Cortes Clinical Professor, Department of Clinical Medicine, Department of Clinical Medicine
Whether exogenous hormones should be used in boys with cryptorchidism (undescended testis, UDT) remains one of the most debated questions in paediatric andrology and urology. European/American practice guidelines no longer recommend hormonal therapy to induce descent, citing low success rates and uncertain long-term benefit, whereas a European panel has a weak recommendation of gonadotropin-releasing hormone (GnRH) analogues as adjuvant therapy to potentially preserve fertility indices in selected boys—especially bilateral cases—after orchidopexy.
This paper reviews histological, endocrine, and clinical evidence for adverse effects of hormonal treatment administered in the prepubertal years, with focus on hCG (human chorionic gonadotropin) and GnRH (LHRH) regimens used historically for “therapeutic descent.” It synthesizes data from Danish and Nordic cohorts (including our own), randomized/controlled studies, and translational work on germ cell apoptosis and suppression of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). Key findings are:
Taken together, available evidence supports the American, Nordic and European consensus position that routine hormonal treatment for cryptorchidism is not recommended—given poor efficacy for descent and possible adverse effects on spermatogenesis—while acknowledging that post-orchiopexy, low-dose adjuvant GnRH analogues may be studied for patients with biopsy-defined reduced germ cell counts and germ cell transformation, and endocrine evaluation revealing insufficient genuine gonadotropin stimulation, under robust protocols.
Keywords
Cryptorchidism
hormonal side effects
histology
Jörgen Thorup
The Department of Pediatric Surgery, Rigshospitalet, Copenhagen, Denmark
Correspondence: Prof Dr med, PhD Jörgen Thorup Rigshospitalet, Department of Transplantation and Digestive Diseases
Cryptorchidism affects ~2–5% of full-term male infants and remains a leading cause of impaired spermatogenesis in adulthood despite contemporary surgical timing. Quantitative histology shows that a subset of cryptorchid testes have markedly reduced germ cells per tubular cross-section (G/T) in early childhood and, in the most severe cases, Sertoli-cell-only (SCO) histology—changes that predict poor fertility regardless of orchiopexy or adjunctive hormonal therapy. Preservation of future reproductive potential for prepubertal boys who cannot produce sperm therefore demands strategies that bank the spermatogonial stem cell (SSC) compartment. Since 2002, hospital programs—first pioneered in Brussels—have offered testicular tissue cryopreservation (TTC) on an experimental basis to prepubertal boys at high risk of infertility, initially those facing gonadotoxic therapies and, progressively, selected boys with cryptorchidism. Parallel laboratory advances have established: (i) long-term survival of human SSCs after xenotransplantation to murine hosts; (ii) in vitro propagation of human spermatogonia; (iii) viability and endocrine functionality of cryopreserved prepubertal human testicular tissue; and (iv) full translational feasibility in a non-human primate model culminating in a live-born rhesus macaque from sperm derived after autologous grafting of cryopreserved prepubertal testis tissue.
Over 25 years, the Copenhagen program and collaborators have contributed key clinical and laboratory milestones: defining age-sensitive germ cell depletion, demonstrating FSH-responsive ex vivo cultures, developing human TTC protocols for boys with cryptorchidism, and characterizing biomarker correlations (notably inhibin B) with G/T to guide selection.
Recent prospective series from Copenhagen (2014–2022) show TTC can be integrated around orchiopexy with high parental acceptance and robust tissue quality, although clinical fertility restoration in humans remains unproven and ethically complex.
In this paper the author argues that TTC may reasonably be considered for a narrowly defined subset of boys with cryptorchidism—specifically those with bilateral disease and severely reduced G/T (≈≤0.2–0.3) or concordant biomarker profiles (very low inhibin B), after thorough counseling that emphasizes experimental status, uncertain timelines, and alternatives. The author synthesizes historical context, mechanistic rationale, translational evidence, clinical selection frameworks, ethics, and a pragmatic pathway to implementation within pediatric andrology services. The conclusion balances prudence with progress: offer TTC selectively today while powering registries and translational pipelines that make tomorrow’s restoration options safe and real.
Keywords
Cryptorchidism
testis
cryopreservation
Domingos T. G. Bica
Department of Pediatric Surgery, Federal University Children’s Hospital, Rio de Janeiro, Brazil.
Correspondence: Prof Dr med. PhD Domingos Bica Federal University Children’s Hospital, Rio de Janeiro, Brazil.
Background. Cryptorchidism (undescended testis, UDT) affects ~2–3% of term male infants and remains the most common genital anomaly of childhood. Beyond malposition, the central clinical problem is impaired germ cell maturation during the mini-puberty window (postnatal surge of GnRH–LH/FSH–testosterone), which in a subset of boys fails to occur, leading to loss of adult dark (Ad) spermatogonia, the stem-cell–like population that predicts future fertility. Surgical repositioning (orchiopexy) addresses location, but not necessarily the endocrine milieu. In the late 1980s–early 1990s, we therefore tested whether a brief course of intranasal buserelin (a GnRH agonist) could (a) induce descent and (b) rescue germ-cell maturation in cryptorchid boys.
Methods. In a randomized, double-blind, placebo-controlled, three-arm trial at the Federal University Children’s Hospital (UFRJ, Rio de Janeiro) with blinded histology processed in Basel, boys with true cryptorchidism were assigned to: (i) placebo; (ii) intranasal buserelin 20 µg once daily for 28 days; or (iii) primary surgery (orchiopexy). Subsequently, undescended testes underwent orchiopexy with bilateral testicular biopsies in all participants to quantify germ cells and maturation indices. Design, dosing, blinding, and histology endpoints are detailed in the primary publications and reiterated in the symposium program and transcript.
Results. In the published trial 59 boys were randomized (22 buserelin, 18 surgery, 19 placebo). Buserelin significantly increased scrotal descent compared with placebo (p < 0.01). Boys treated with buserelin had the highest number and maturation index of germ cells; epididymal development and closure of the processus vaginalis were also more favorable in the buserelin group (p < 0.003 and p < 0.05, respectively). The surgical arm appropriately repositioned testes but, as expected, did not itself reproduce the endocrine environment of mini-puberty. Subsequent follow-up and translational work showed that presence of Ad spermatogonia after endocrine therapy predicts better fertility potential; conversely, boys lacking Ad spermatogonia (impaired mini-puberty) face persistently reduced fertility prospects despite anatomically successful surgery.
Conclusions. A short, low-dose buserelin course can, in carefully selected boys, (i) induce descent when the testis is near the scrotum and (ii) support germ-cell maturation, a
biologically meaningful endpoint that surgery alone cannot provide. Modern guidelines still recommend early orchiopexy (by 6–18 months) and generally discourage routine hormonal therapy for descent because population-level response rates are modest and heterogeneous; however, converging histologic and molecular data indicate that adjuvant GnRH-agonist treatment may be valuable for the subset with endocrine-mini-puberty failure and poor Ad-spermatogonia counts. This talk revisits the design, outcomes, and lessons of the Rio–Basel RCT, addresses controversies, and frames a pragmatic, risk-stratified approach that integrates histology with contemporary care pathways.
Keywords
Cryptorchidism
treatment
Buserelin
three arm placebo-controlled study
histology
Ad spermatogonia
Dimitrios T. Papadimitriou
Department of Pediatric-Adolescent Endocrinology & Diabetes, Athens Medical Center, Athens, Greece.
Correspondence: jnfo@pedoendo.gr
Background. “Mini-puberty” is the transient activation of the hypothalamic–pituitary–gonadal (HPG) axis from ~2 weeks to 3–6 months in boys, driving Leydig- and Sertoli-cell activity, penile and testicular growth, and programming of future fertility. In congenital hypogonadotropic hypogonadism (CHH)—including Kallmann syndrome—this surge is absent, leading to micropenis and bilateral cryptorchidism despite otherwise normal anatomy. Because classical treatment paradigms address phenotype later (testosterone for penile length; surgery for testicular position), they often miss this early physiologic window and may not fully rescue fertility potential.
Objective. To synthesize the rationale, physiology, and clinical evidence for replacement of male mini-puberty using exogenous gonadotropins (recombinant LH/FSH) and related strategies, anchored in the author’s REMAP program and subsequent literature.
Methods & Sources. Narrative review with emphasis on endocrine physiology, translational studies, and prospective case series/registries. Core primary sources include the author’s REMAP study (“Replacement of Male Mini-Puberty”), ESPE abstracts, and the ISRCTN registry, alongside contemporary reviews and consensus statements.
Findings. In neonates/infants with CHH and absent mini-puberty, daily subcutaneous recombinant LH/FSH (typically 75/150 IU; Pergoveris®) for 3 months reproducibly: (i) raises LH/FSH to postnatal physiologic ranges; (ii) drives testosterone into pubertal levels; (iii) normalizes inhibin B and AMH; (iv) increases penile length from <2 cm to ≈3.5–4.0 cm median; (v) induces testicular descent to the scrotum or low inguinal canal with volumes
~1.5–2.5 mL; and (vi) initiates catch-up growth—all with acceptable short-term safety. Limited follow-up suggests sustained scrotal position in most; occasional low inguinal re-migration is manageable surgically. Mechanistically, therapy mimics the physiologic surge, restoring Leydig/Sertoli interplay that can never be recaptured by late adolescence-onset induction alone.
Conclusions. For appropriately selected boys with documented absence of mini-puberty and CHH (especially those with bilateral non-palpable testes and micropenis), gonadotropin replacement in early infancy provides a physiologic, noninvasive means to repair micropenis, facilitate or complete testicular descent, and likely preserve fertility potential. Programs should be embedded within multidisciplinary DSD/andrology networks with standardized diagnostics, dosing, monitoring, and long-term outcome registries.
Keywords
Cryptorchidism
hyogonagotrope
hypogonadism
pergoveris treatment
Faruk Hadziselimovic
Cryptorchidism research institute, Liestal, Switzerland
Correspondence: Dr med em. Faruk Hadziselimovic Bahnhofplatz 11,4410 Liestal Switzerland
Combining histology, endocrinology, and transcriptomics, this paper presents molecular proof that mini-puberty failure—not malposition alone—causes infertility in many cryptorchid boys. GnRH agonist therapy (e.g. buserelin) restores the expression of genes involved in germ-cell maturation (NHLH2, PRDMs, and PIWI/TDRD pathways), thereby re-establishing mini-puberty. We argue that early surgery should be complemented by individualized hormonal therapy as a fertility-preserving intervention in a biopsy-selected subset of cryptorchid boys.
Keywords
Cryptorchidism
RNA sequencing
GnRHa treatment
Mini-puberty
Infertility
Luciano Alves Favorito
Urogenital Research Unit, State University of Rio de Janeiro, Brazil
Correspondence: Prof Dr med , PhD Luciano Favorito State University of Rio de Janeiro, Brazil
Background. Testicular descent is a complex, two-stage developmental program that brings the fetal testis from the abdomen into the scrotum. Central to this process is the gubernaculum testis, a mesenchymal, ligament-like structure that grows, swells, remodels, and ultimately regresses as the testis completes its migration. Failures anywhere along this pipeline manifest
as cryptorchidism, with downstream risks for subfertility and malignancy. Although hormones (INSL3, testosterone), the genitofemoral nerve (GFN)/CGRP axis, intra-abdominal pressure, and the processus vaginalis have been studied for decades, a translational synthesis focused on gubernacular structure–function and its practical consequences for pediatric urology is timely.
Objective: To describe the anatomy, histomorphometry, biochemistry, innervation, and vascular anatomy of the gubernaculum and its attachments — translating these insights into operative decision-making (orchiopexy, Fowler–Stephens strategy) and into the interpretation of clinical heterogeneity (ascended testis, ectopias, Prune-Belly syndrome (PBS).
Methods. In this narrative review we showed some topics on: (A) fetal dissection series mapping migration chronology and distal gubernacular insertions; (B) morphometric/ultrastructural analyses of the gubernacular matrix in normal fetuses, undescended/ascended testis, and PBS; (C) arterial supply to the fetal testis during descent; and (D) classification and prevalence of epididymal anomalies relevant to obstructive infertility. Findings are contextualized with seminal work on endocrine and neural regulation of descent and with the conference transcript guiding the present talk.
Results. The gubernaculum undergoes stage-specific remodeling: early hydration and GAG richness (facilitating swelling and guidance), then a progressive cellular rarefaction occurs as the testis reaches the scrotum. Distal insertions show meaningful variation, including rare perineal, femoral, contralateral scrotal, and pubopenile attachments that explain
diverse testicular ectopias; asymmetric migration is uncommon but real. The fetal testis has multiple arterial inputs (testicular, deferential, cremasteric) in the majority of specimens, supporting Fowler–Stephens testicular mobilization when necessary. Epididymal anomalies — disjunction at head/tail or total separation — occur in a clinically relevant minority, particularly in bilateral UDT, and can underlie obstructive infertility despite technically successful orchiopexy.
Conclusions. The gubernaculum is not a passive tether but the anatomical driver and interpreter of multiple signals orchestrating descent. Understanding its microstructure, insertions, innervation, and vascular context sharpens surgical planning, explains hormonal treatment variability, and refines prognostication. Translational adoption of these principles can reduce redo operations, anticipate ectopias, and inform fertility counseling.
Keywords
Gubernaculum
testicular descent
cryptorchidism
Dragana Živković
Faculty of Medicine, University of Novi Sad, 21000 Novi Sad, Serbia. The Institute for Children and Youth Health Care of Vojvodina, 21000 Novi Sad, Serbia.
Correspondence; Prof Dr med. PhD Dragana Živković University of Novi Sad, 21000 Novi Sad, Serbia.
Accurate clinical distinction among undescended, ectopic, retractile and acquired/ascending testes underpins every subsequent decision in cryptorchidism. Misclassification drives both over- and under-treatment, with repercussions for fertility preservation, malignancy surveillance, resource use, and family counseling. This paper synthesizes practical pitfalls encountered from referral to definitive management, aligning bedside examination with contemporary guideline recommendations and translational insights. Drawing from our clinical program in Novi Sad and collaborative work with Faruk Hadžićselimović and colleagues, we emphasize five recurring traps: (1) equating any “empty” hemiscrotum with an undescended testis; (2) over-reliance on ultrasonography for palpable testes or to “rule in” non-palpable testes; (3) under-recognition of acquired/ascending testes and retractile physiology; (4) treating heterogeneous risk categories as homogeneous—particularly when biopsy interpretation is unavailable or suboptimal; and (5) ignoring environmental and systemic contexts that modulate risk and presentation. We propose a streamlined diagnostic pathway that privileges meticulous physical examination, judicious use of laparoscopy for non-palpable testes, selective adjunct testing, and context-aware counseling. Throughout, we integrate histological and molecular evidence (e.g., adult-dark [Ad] spermatogonia as a prognostic marker) to show how apparently “simple” diagnostic slips alter life-course outcomes.
Keywords
Cryptorchidism
pitfalls
treatment
Faruk Hadziselimovic
Cryptorchidism Research Institute, Liestal, Switzerland
Correspondence: Dr med em. Faruk Hadziselimovic Bahnhofplatz 11,4410 Liestal Switzerland
The descent of the male gonad is a coordinated morphogenetic journey of the epididymo-testicular unit, not of the testis in isolation. A century of schematic drawings placed the gubernaculum at center stage, but histology, comparative embryology, and translational studies have indicated that the epididymis precedes and “leads” the testis into the scrotum, with the gubernaculum primarily creating the path and providing space rather than “towing” the testis. This paper synthesizes molecular, anatomical, and clinical evidence supporting this epididymis-first concept and revisits classic experimental data to integrate modern insights on INSL3/RXFP2 signaling and androgen action. I also discuss how dissociation anomalies between the epididymis and testis, as well as a failure of epididymal smooth muscle/myofibroblast maturation, can arrest descent despite apparently intact gubernacular morphology.
Keywords
Gubernaculum
Embryology
Epididymis
Hypogonadotropic hypogonadism
GnRHa
Zacharias Zachariou
Medical School, University of Cyprus, Nicosia, Cyprus.
Correspondence; Prof Dr med PhD em. Zacharias Zachariou University of Cyprus, Nicosia, Cyprus
The optimal timing of orchidopexy for cryptorchidism remains debated despite guidelines favoring repair between 6–12 months; this narrative synthesis integrates histologic, endocrine, and clinical outcome data — framed by the symposium transcript from Vassalli Hall — to evaluate the advantages and disadvantages of early surgery. Earlier orchidopexy (≤12 months) is consistently associated with better postoperative testicular growth and germ-cell preservation, with surrogate markers of fertility (germ-cell counts, semen parameters) generally superior to those seen after delayed repair. However, recent series show comparable rates of testicular atrophy and perioperative complications across early and later cohorts in experienced hands.
Countervailing considerations include the possibility of intrinsic, irreversible testicular defects that limit benefit, technical and anesthetic challenges in smaller infants, and the risk of unnecessary operations stemming from diagnostic inaccuracy, all compounded by persistent real-world delays that undermine adherence to early-repair guidance. Overall, the weight of evidence supports early orchidopexy — ideally between 6 and 12 months — as the strategy most likely to preserve testicular tissue and enhance future fertility without increasing operative risk, while emphasizing individualized planning for high intra-abdominal testes and the need for standardized outcomes and long-term fertility (live-birth) endpoints to definitively quantify benefit.
Keywords
Cryptorchidism
early orchidopexy
strategy
Guy Bogaert
UZ Leuven KULeuven Dept of Urology, Herestraat, 49, B – 3000, Leuven, Belgium.
Correpondence; Prof Dr med. PhD em. Guy Bogaert Herestraat, 49, B – 3000, Leuven, Belgium
Cryptorchidism is a symptom with multifactorial etiologies that range from endocrine signaling failure and epididymo-gubernacular mechanics to primary testicular dysgenesis. In contemporary practice, surgical orchidolyse and orchidopexy is standardized and widely successful at placing the testis in its normal scrotal environment; however, hormonal therapy remains controversial. This paper synthesizes translational and clinical evidence—including guideline positions, randomized trials, meta-analyses, long-term cohort data, and biopsy-based histology—to appraise the benefits and drawbacks of (1) primary hormonal treatment and (2) adjunctive hormonal therapy after successful orchidopexy, alongside (3) the benefits and limitations of orchidopexy itself. Special attention is given to fertility-relevant endpoints (Ad spermatogonia, inhibin B, semen analysis) and real-world outcomes such as paternity.
We conclude that primary hormonal therapy should not be used to induce descent, but carefully selected, low-dose, intermittent GnRH analog therapy after orchidopexy may benefit germ-cell maturation in boys with congenital true cryptorchidism and boys with bilateral ascending cryptorchidism and proven histological low fertility potential, whereas orchidopexy—performed expertly and early (ideally ≤12–18 months)—remains the gold standard for durable scrotal positioning, improved testicular growth trajectories, and facilitation of surveillance. The decision to offer adjuvant hormonal therapy should be individualized, biopsy-informed when feasible, and framed by shared decision-making about uncertain long-term fertility gains.
Keywords
Cryptorchidism
hormonal treatment
orchidopexy
Beata Vincel (Vilnius)
Children’s Surgery Centre, Clinic of Gastroenterology, Nephrourology and Surgery, Institute of Clinical Medicine, Vilnius, Lithuania
Correspondence; Dr med PhD Beta Vincel Institute of Clinical Medicine, Vilnius, Lithuania
International guidance on cryptorchidism has been shaped by three reference documents: the Nordic consensus (2007), the American Urological Association (AUA) guideline (2014), and the periodically updated European Association of Urology/European Society for Paediatric Urology (EAU/ESPU) guidelines, which were most recently revised in 2024. These statements agree regarding early orchidopexy (generally before 12–18 months of age), avoidance of routine imaging before specialist referral, and laparoscopy for non-palpable testicles. Clinical studies demonstrate that surgery alone—even early and expertly performed surgery—does not fully restore male reproductive potential in 50% of cryptorchid boys belonging to the high infertility risk (HIR) group. This patient group suffers hypogonadotropic hypogonadism, such that the logical treatment approach includes hormonal replacement.
Since the drafting of the main reference guidelines, emerging translational evidence has refined our understanding of the biology of mini-puberty, the prognostic value of Ad spermatogonia, and the molecular/epigenetic landscape that underpins impaired germ-cell maturation in cryptorchidism. The present review appraises which aspects of contemporary guidance remain robust, which recommendations lag behind new data, and where pragmatic multidisciplinary updates are likely warranted. It concludes with targeted proposals aimed at aligning future guidance with the latest science, while preserving the feasibility of implementation across varied health systems.
Keywords
Cryptorchidism
treatment
surgery
hormones