-
Current Opinion in Cell Biology Dec 2020Spermatogonial stem cells (SSCs) are essential for long-term spermatogenesis and are the subject of considerable clinical interest, as 'SSC therapy' has the potential to... (Review)
Review
Spermatogonial stem cells (SSCs) are essential for long-term spermatogenesis and are the subject of considerable clinical interest, as 'SSC therapy' has the potential to cure some forms of male infertility. Recently, we have learned more about SSCs and spermatogenesis in general from a plethora of studies that performed single-cell RNA sequencing (scRNAseq) analysis on dissociated cells from human, macaque, and/or mice testes. Here, we discuss what scRNAseq analysis has revealed about SSC precursor cells, the initial generation of SSCs during perinatal development, and their heterogeneity once established. scRNAseq studies have also uncovered unexpected heterogeneity of the larger class of cells that includes SSCs - undifferentiated spermatogonia. This raises the controversial possibility that multiple SSC subsets exist, which has implications for mechanisms underlying spermatogenesis and future SSC therapeutic approaches.
Topics: Animals; Humans; Male; Models, Biological; Single-Cell Analysis; Spermatogenesis; Spermatogonia; Stem Cells; Testis
PubMed: 32950921
DOI: 10.1016/j.ceb.2020.07.005 -
Toxicological Sciences : An Official... Oct 2020Studies have shown that mammalian testes, in particular the Sertoli cells, are highly susceptible to exposure of environmental toxicants, such as cadmium,... (Review)
Review
Studies have shown that mammalian testes, in particular the Sertoli cells, are highly susceptible to exposure of environmental toxicants, such as cadmium, perfluorooctanesulfonate, phthalates, 2,5-hexanedione and bisphenol A. However, important studies conducted by reproductive toxicologists and/or biologists in the past have been treated as toxicology reports per se. Yet, many of these studies provided important mechanistic insights on the toxicant-induced testis injury and reproductive dysfunction, relevant to the biology of the testis and spermatogenesis. Furthermore, recent studies have shown that findings obtained from toxicant models are exceedingly helpful tools to unravel the biology of testis function in particular spermatogenesis, including specific cellular events associated with spermatid transport to support spermiogenesis and spermiation. In this review, we critically evaluate some recent data, focusing primarily on the molecular structure and role of microtubules in cellular function, illustrating the importance of toxicant models to unravel the biology of microtubule cytoskeleton in supporting spermatogenesis, well beyond information on toxicology. These findings have opened up some potential areas of research which should be carefully evaluated in the years to come.
Topics: Animals; Cytoskeleton; Hazardous Substances; Male; Microtubules; Sertoli Cells; Spermatogenesis; Testis
PubMed: 32647867
DOI: 10.1093/toxsci/kfaa109 -
Folia Morphologica 2021This study aimed to compare the isolated testes size, volume, weight and density changes with age and to establish the suitability of three formulas of testicular volume...
BACKGROUND
This study aimed to compare the isolated testes size, volume, weight and density changes with age and to establish the suitability of three formulas of testicular volume calculation for 18-50 and 51-70-year-old men groups.
MATERIALS AND METHODS
Two hundred and six testes of 103 men (59 of 18-50-year-old and 44 of 51-70-year-old men) were weighed and their size was measured by the sliding calliper. The accurate volume was determined by water displacement and compared with volume calculated using three formulas, and the density of testicular tissues was calculated.
RESULTS
The mean length and height of both testes and length and height of right and left testes decreased significantly with age. The mean width of both testes and width of right and left testes decreased with age insignificantly. The mean of water displacement volume and weight and volume and weight of right and left testes decreased with age significantly. The mean density of testicular tissues and the density of the right and left testes increased significantly with age. In the same age group, the size, water displacement volume and weight of right testes was insignificantly higher than that of the left ones, and the density of testicular tissues was similar in the right and left testes.
CONCLUSIONS
The prolate spheroid formula was most suitable for calculation of testicular volume for 18-50-year-old men and prolate ellipsoid formula was most suitable for calculation of testicular volume in 51-70-year-old men.
Topics: Adolescent; Adult; Aged; Humans; Male; Middle Aged; Organ Size; Testis; Ultrasonography; Young Adult
PubMed: 32207852
DOI: 10.5603/FM.a2020.0033 -
International Journal of Molecular... May 2024The testes serve as the primary source of androgens and the site of spermatogenesis, with their development and function governed by hormonal actions via endocrine and... (Review)
Review
The testes serve as the primary source of androgens and the site of spermatogenesis, with their development and function governed by hormonal actions via endocrine and paracrine pathways. Male fertility hinges on the availability of testosterone, a cornerstone of spermatogenesis, while follicle-stimulating hormone (FSH) signaling is indispensable for the proliferation, differentiation, and proper functioning of Sertoli and germ cells. This review covers the research on how androgens, FSH, and other hormones support processes crucial for male fertility in the testis and reproductive tract. These hormones are regulated by the hypothalamic-pituitary-gonad (HPG) axis, which is either quiescent or activated at different stages of the life course, and the regulation of the axis is crucial for the development and normal function of the male reproductive system. Hormonal imbalances, whether due to genetic predispositions or environmental influences, leading to hypogonadism or hypergonadism, can precipitate reproductive disorders. Investigating the regulatory network and molecular mechanisms involved in testicular development and spermatogenesis is instrumental in developing new therapeutic methods, drugs, and male hormonal contraceptives.
Topics: Humans; Male; Testis; Animals; Spermatogenesis; Follicle Stimulating Hormone; Hypothalamo-Hypophyseal System; Androgens; Testosterone
PubMed: 38891991
DOI: 10.3390/ijms25115805 -
Cells Jan 2022Spermatogenesis is a complex process occurring in mammalian testes, and constant sperm production depends on the exact regulation of the microenvironment in the testes.... (Review)
Review
Spermatogenesis is a complex process occurring in mammalian testes, and constant sperm production depends on the exact regulation of the microenvironment in the testes. Many studies have indicated the crucial role of blood-testis barrier (BTB) junctions and retinoic acid (RA) signaling in the spermatogenesis process. The BTB consists of junctions between adjacent Sertoli cells, comprised mainly of tight junctions and gap junctions. In vitamin A-deficient mice, halted spermatogenesis could be rebooted by RA or vitamin A administration, indicating that RA is absolutely required for spermatogenesis. Accordingly, this manuscript will review and discuss how RA and the BTB regulate spermatogenesis and the interaction between RA signaling and BTB function.
Topics: Animals; Blood-Testis Barrier; Male; Mammals; Mice; Sertoli Cells; Spermatogenesis; Tretinoin; Vitamin A
PubMed: 35159162
DOI: 10.3390/cells11030352 -
Andrology Jan 2021The recent report of SARS-CoV-2 presence in semen samples of six patients, including two subjects who were recovering from the clinical disease, re-opened the discussion... (Review)
Review
BACKGROUND
The recent report of SARS-CoV-2 presence in semen samples of six patients, including two subjects who were recovering from the clinical disease, re-opened the discussion on possible male genital tract infection, virus shedding in semen, sexual transmission and safety of fertility treatments during the pandemic period.
OBJECTIVES
To explore current data and hypothesis on the possible sites of SARS-CoV-2 infection in the male reproduction system.
MATERIALS AND METHODS
We reviewed the current literature to describe: a) the evidences on angiotensin-converting enzyme 2 (AC2E) and transmembrane serine protease 2 (TMPRSS2) expression in the testes, accessory glands (including prostate) and the urinary tract; b) other coronaviruses' (SARS and MERS) ability to infect these sites.
RESULTS
The co-expression of both ACE2 and TMPRSS2 genes was reported in spermatogonial stem cells, elongated spermatids, in at least a small percentage of prostate hillock cells and in renal tubular cells. Testicular damage was described in autopsies of SARS patients, without evidence of the virus in the specimens. Prostate is a known infection site for MERS-CoV. SARS-CoV-2 was detected in urines.
DISCUSSION
There are still al lot of open questions on the effects of SARS-CoV-2 infection on the male reproductive tract. The presence of receptors is not a proof that the testis provides a site for viral infection and it is still unknown if SARS-CoV-2 is capable to pass the blood-testis barrier. The possibility of a prostate involvement has not been investigated yet: we have no data, but theoretically it cannot be excluded. Moreover, the RNA detected in semen could have been just a residual of urinary shedding.
CONCLUSION
Opening our prospective beyond the testis could be the key to better understand the possibility of a semen-related viral transmission as well as COVID19 short and long-term effects on male reproductive function.
Topics: Angiotensin-Converting Enzyme 2; COVID-19; Humans; Male; Receptors, Virus; SARS-CoV-2; Semen; Serine Endopeptidases; Testis; Virus Internalization; Virus Shedding
PubMed: 32533891
DOI: 10.1111/andr.12839 -
ELife Mar 2022Sensory systems must account for both contextual factors and prior experience to adaptively engage with the dynamic external environment. In the central auditory system,...
Sensory systems must account for both contextual factors and prior experience to adaptively engage with the dynamic external environment. In the central auditory system, neurons modulate their responses to sounds based on statistical context. These response modulations can be understood through a hierarchical predictive coding lens: responses to repeated stimuli are progressively decreased, in a process known as repetition suppression, whereas unexpected stimuli produce a prediction error signal. Prediction error incrementally increases along the auditory hierarchy from the inferior colliculus (IC) to the auditory cortex (AC), suggesting that these regions may engage in hierarchical predictive coding. A potential substrate for top-down predictive cues is the massive set of descending projections from the AC to subcortical structures, although the role of this system in predictive processing has never been directly assessed. We tested the effect of optogenetic inactivation of the auditory cortico-collicular feedback in awake mice on responses of IC neurons to stimuli designed to test prediction error and repetition suppression. Inactivation of the cortico-collicular pathway led to a decrease in prediction error in IC. Repetition suppression was unaffected by cortico-collicular inactivation, suggesting that this metric may reflect fatigue of bottom-up sensory inputs rather than predictive processing. We also discovered populations of IC units that exhibit repetition enhancement, a sequential increase in firing with stimulus repetition. Cortico-collicular inactivation led to a decrease in repetition enhancement in the central nucleus of IC, suggesting that it is a top-down phenomenon. Negative prediction error, a stronger response to a tone in a predictable rather than unpredictable sequence, was suppressed in shell IC units during cortico-collicular inactivation. These changes in predictive coding metrics arose from bidirectional modulations in the response to the standard and deviant contexts, such that the units in IC responded more similarly to each context in the absence of cortical input. We also investigated how these metrics compare between the anesthetized and awake states by recording from the same units under both conditions. We found that metrics of predictive coding and deviance detection differ depending on the anesthetic state of the animal, with negative prediction error emerging in the central IC and repetition enhancement and prediction error being more prevalent in the absence of anesthesia. Overall, our results demonstrate that the AC provides cues about the statistical context of sound to subcortical brain regions via direct feedback, regulating processing of both prediction and repetition.
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Auditory Pathways; Auditory Perception; Inferior Colliculi; Mice; Optogenetics
PubMed: 35290181
DOI: 10.7554/eLife.73289 -
Andrology Nov 2021Testis cord elongation and coiling, which occur in the final stage of testis formation, have been attributed to Sertoli cell proliferation; however, the underlying...
BACKGROUND
Testis cord elongation and coiling, which occur in the final stage of testis formation, have been attributed to Sertoli cell proliferation; however, the underlying mechanisms remain unclear.
OBJECTIVE
The aim of the present study was to clarify the precise three-dimensional structure of testis cords in the final stage of testis formation in mice and rats.
MATERIALS AND METHODS
We reconstructed whole testis cords in the final stage of testis formation in mice (on embryonic days 15.5 and 18.5) and rats (on embryonic days 16.5 and 19.5) using serial paraffin sections and high-performance three-dimensional reconstruction software.
RESULTS
Detailed morphometric parameters were calculated for three-dimensionally reconstructed testis cords in six mouse and rat testes each. The mean numbers of testis cords in mice and rats were 12.7 and 27.8, respectively. The mean number of branching points per testis cord was 1.52 in mice, whereas it was only 0.30 in rats. In contrast, the mean ratio of the inner cords, that is, cords not in contact with the tunica albuginea, was 23.0% in rats, whereas it was only 6.5% in mice. In both species, the cords on the cranial side coiled more strongly than those on the caudal side, consistent with the greater expansion of the testis volume on the caudal side. All cords formed right-handed helices from the rete testis side.
DISCUSSION AND CONCLUSIONS
The present results suggest that testis cords undergo anastomosis at a higher frequency in mice than in rats and that the coiling of testis cords proceeds from the cranial to caudal side of the testis in both species.
Topics: Animals; Cell Proliferation; Imaging, Three-Dimensional; Male; Mice; Models, Anatomic; Models, Animal; Rats; Sertoli Cells; Spermatic Cord; Testis
PubMed: 34128333
DOI: 10.1111/andr.13069 -
Journal of Medical Case Reports Dec 2023Accessory splenic tissue is a commonly encountered phenomenon in medical literature. Typically, these accessory spleens are found in close proximity to the main spleen,...
BACKGROUND
Accessory splenic tissue is a commonly encountered phenomenon in medical literature. Typically, these accessory spleens are found in close proximity to the main spleen, either in the hilum or within the surrounding ligaments. Nevertheless, it is noteworthy that they can also be located in unusual sites such as the jejunum wall, mesentery, pelvis, and, exceptionally rarely, the scrotum. The first documented case of accessory splenic tissue in the scrotum was reported by Sneath in 1913 and is associated with a rare congenital anomaly called splenogonadal fusion. This report describes an infant who presented with a scrotal mass noted by his mother and after examination, investigations, and surgical exploration, it was revealed to be splenogonadal fusion.
CASE DESCRIPTION
An 8-month-old Caucasian male patient presented with a mass in the left testicle and bluish discoloration of the scrotum, which had been incidentally noticed in the previous 2 months. The general physical examination was unremarkable. Other than a palpable scrotal mass that was related to the upper pole of the testis, the rest of examination was unremarkable. Imaging revealed that this mass originated from the tail of the epididymis without infiltrating the testis and tumor markers were normal. On inguinal exploration, a reddish brown 2 × 2 cm mass was found attached to the upper pole and was completely excised without causing any harm to the testis, vessels, or epididymis. Histopathological evaluation confirmed the presence of intratesticular ectopic splenic tissue.
CONCLUSION
Although uncommon, splenogonadal fusion can be included in the differential diagnosis of a testicular swelling. Accurate diagnosis allows for appropriate treatment planning which helps to avoid unnecessary radical orchiectomy, which can have a significant impact on the patient's reproductive and psychological wellbeing.
Topics: Infant; Humans; Male; Testis; Splenic Diseases; Orchiectomy; Scrotum; Digestive System Abnormalities
PubMed: 38098099
DOI: 10.1186/s13256-023-04241-0 -
Cell Cycle (Georgetown, Tex.) 2021Expansion of the coding and regulatory capabilities of eukaryotic transcriptomes by alternative splicing represents one of the evolutionary forces underlying the... (Review)
Review
Expansion of the coding and regulatory capabilities of eukaryotic transcriptomes by alternative splicing represents one of the evolutionary forces underlying the increased structural complexity of metazoans. Brain and testes stand out as the organs that mostly exploit the potential of alternative splicing, thereby expressing the largest repertoire of splice variants. Herein, we will review organ-specific as well as common mechanisms underlying the high transcriptome complexity of these organs and discuss the impact exerted by this widespread alternative splicing regulation on the functionality and differentiation of brain and testicular cells.
Topics: Animals; Brain; Cell Differentiation; Humans; Male; RNA Splicing; Spermatogenesis; Testis; Transcriptome
PubMed: 33632061
DOI: 10.1080/15384101.2021.1889187