Male and female gonadal ageing: its impact on health span and life span

Black Chokeberry (Aronia melanocarpa) Juice Supplementation Improves Oxidative Stress and Aging Markers in Testis of Aged Rats

Spermatogenesis is a process that continues until the end of an individual's life, although with reduced activity with advancing age. Inflammation, oxidation, and apoptosis are events considered as predictors of pathogenesis and the development of age-related diseases observed in aged testes. The use of natural compounds with antioxidant and anti-inflammatory properties has a beneficial effect on the inflammatory and oxidative status of the aged testis. The aim of this study was to determine the effect of supplementation with antioxidant-rich black chokeberry (Aronia melanocarpa) juice on several markers of oxidative stress and aging in rat testis. In total, 24 male Wistar rats were divided into three experimental groups: young controls aged 2 months, old controls aged 27 months, and 27-month-old rats supplemented with black chokeberry juice at a dose of 10 mL/kg for 3 months. A. melanocarpa juice supplementation led to reduced oxidative stress, manifested by increased immunoexpression of nNOS, eNOS, and MAS1 in the seminiferous tubules and in the Leydig cells. The morphometrically determined tubule structure data showed no significant differences between the three groups. However, the intensity of the immunoreaction for TRK-C and NT3 in Leydig cells was demonstrably higher in the supplemented old animals compared with the old controls. There was a significantly higher number of blood vessels around the seminiferous tubules in the supplemented animals compared to the old controls. These data indicate that supplementation with A. melanocarpa juice slows down aging processes in the testis and preserves the functional activity of Leydig cells.

Single-cell transcriptomics identifies senescence-associated secretory phenotype (SASP) features of testicular aging in human

The male reproductive system experiences degradation with age, predominantly impacting the testes. Testicular aging can result in failure to produce physiological testosterone levels, normal sperm concentrations, or both. However, we cannot predict the onset of testicular aging in advance. Using single-cell RNA sequencing (scRNA-seq) from Gene Expression Omnibus (GEO) database, we conducted cell-cell communication network of human testis between older and young group, indicating Leydig cells' potential role in spermatogenesis microenvironment of aging testis. And we depicted the senescence-Associated Secretory Phenotype (SASP) features of aging testis by identifying differentially expressed senescence-associated secretory phenotype (SASP)-related genes between two group. Notably, IGFBP7 mainly expressed in Leydig cells of those differentially expressed SASP-related genes in aging testis. Furthermore, IGFBP7 protein located in the interstitial compartment of older mice confirmed by immunofluorescence and highly expressed in both human seminal plasma and mouse testis in the older group confirmed through Western blot. Together, our findings suggest that IGFBP7 may be a new biomarker of testicular aging.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Exosomes Rescue Testicular Aging

BACKGROUND

Testicular aging is associated with diminished fertility and certain age-related ailments, and effective therapeutic interventions remain elusive. Here, we probed the therapeutic efficacy of exosomes derived from human umbilical cord mesenchymal stem cells (hUMSC-Exos) in counteracting testicular aging.

METHODS

We employed a model of 22-month-old mice and administered intratesticular injections of hUMSC-Exos. Comprehensive analyses encompassing immunohistological, transcriptomic, and physiological assessments were conducted to evaluate the effects on testicular aging. Concurrently, we monitored alterations in macrophage polarization and the oxidative stress landscape within the testes. Finally, we performed bioinformatic analysis for miRNAs in hUMSC-Exos.

RESULTS

Our data reveal that hUMSC-Exos administration leads to a marked reduction in aging-associated markers and cellular apoptosis while promoting cellular proliferation in aged testis. Importantly, hUMSC-Exos facilitated the restoration of spermatogenesis and elevated testosterone synthesis in aged mice. Furthermore, hUMSC-Exos could attenuate inflammation by driving the phenotypic shift of macrophages from M1 to M2 and suppress oxidative stress by reduced ROS production. Mechanistically, these efficacies against testicular aging may be mediated by hUMSC-Exos miRNAs.

CONCLUSIONS

Our findings suggest that hUMSC-Exos therapy presents a viable strategy to ameliorate testicular aging, underscoring its potential therapeutic significance in managing testicular aging.

A single-cell transcriptomic landscape of mouse testicular aging

INTRODUCTION

Advanced paternal age of reproduction is an increasing trend, especially in developed countries and areas. This trend results in elevated risks of adverse reproductive outcomes such as reduced fertility rates, increased pregnancy loss, and poor childhood health. Yet, a systematic profiling of aging-associated molecular and cellular alterations in testicular tissue is still missing.

OBJECTIVES

We aimed to dissect aging-associated molecular characteristics in testes of mice.

METHODS

Single-cell transcriptomic sequencing and analysis were conducted in testes of young (2 months old) and old mice (24 months old). Immunofluorescences and immunochemistry were used to characterize aging-associated phenotypes and verify single cell sequence results.

RESULTS

Here, we constructed the first single-cell transcriptomic atlases of testes of young and old mice. In-depth dissection of aging-dependent transcriptional alterations in specific cell types revealed multiple dysregulated biological processes such as increased 'senescence-associated secretory phenotype' and 'inflammation', which were major aging-associated characteristics. Further analysis of aging-related differentially expressed genes uncovered a disrupted balance of undifferentiated and differentiated spermatogonia stem cells in spermatogonia, indicative of a potential role of spermatogonia stem cells in aging-associated subfertility. Importantly, for the first time, our results identified an increased subtype of aging-specific macrophages, which may contribute to a hostile proinflammatory microenvironment during testicular aging.

CONCLUSION

Taken together, our findings depict the distinct single-cell transcriptional features of the aged mouse testes and provide enormous resources for a comprehensive understanding of the cell-type-specific molecular mechanisms underlying mouse testicular aging, which may shed light on developing novel potential diagnostic biomarkers and therapeutic targets for age-associated male subfertility.

Reappraisal of the Concept of Accelerated Aging in Neurodegeneration and Beyond

BACKGROUND

Genetic and epigenetic changes, oxidative stress and inflammation influence the rate of aging, which diseases, lifestyle and environmental factors can further accelerate. In accelerated aging (AA), the biological age exceeds the chronological age.

OBJECTIVE

The objective of this study is to reappraise the AA concept critically, considering its weaknesses and limitations.

METHODS

We reviewed more than 300 recent articles dealing with the physiology of brain aging and neurodegeneration pathophysiology.

RESULTS

(1) Application of the AA concept to individual organs outside the brain is challenging as organs of different systems age at different rates. (2) There is a need to consider the deceleration of aging due to the potential use of the individual structure-functional reserves. The latter can be restored by pharmacological and/or cognitive therapy, environment, etc. (3) The AA concept lacks both standardised terminology and methodology. (4) Changes in specific molecular biomarkers (MBM) reflect aging-related processes; however, numerous MBM candidates should be validated to consolidate the AA theory. (5) The exact nature of many potential causal factors, biological outcomes and interactions between the former and the latter remain largely unclear.

CONCLUSIONS

Although AA is commonly recognised as a perspective theory, it still suffers from a number of gaps and limitations that assume the necessity for an updated AA concept.

The gut metabolite 3-hydroxyphenylacetic acid rejuvenates spermatogenic dysfunction in aged mice through GPX4-mediated ferroptosis

BACKGROUND

Aging-related fertility decline is a prevalent concern globally. Male reproductive system aging is mainly characterized by a decrease in sperm quality and fertility. While it is known that intestinal physiology changes with age and that microbiota is shaped by physiology, the underlying mechanism of how the microbiota affects male reproductive aging is still largely unexplored.

RESULTS

Here, we utilized fecal microbiota transplantation (FMT) to exchange the fecal microbiota between young and old mice. Cecal shotgun metagenomics and metabolomics were used to identify differences in gut microbiota composition and metabolic regulation during aging. Our results demonstrated that FMT from young to old mice alleviated aging-associated spermatogenic dysfunction through an unexpected mechanism mediated by a gut bacteria-derived metabolite, 3-hydroxyphenylacetic acid (3-HPAA). 3-HPAA treatment resulted in an improvement of spermatogenesis in old mice. RNA sequencing analysis, qRT-PCR and Western blot revealed that 3-HPAA induced an upregulation of GPX4, thereby restraining ferroptosis and restoring spermatogenesis. These findings were further confirmed by in vitro induction of ferroptosis and inhibition of GPX4 expression.

CONCLUSIONS

Our results demonstrate that the microbiome-derived metabolite, 3-HPAA, facilitates spermatogenesis of old mice through a ferroptosis-mediated mechanism. Overall, these findings provide a novel mechanism of dysregulated spermatogenesis of old mice, and suggest that 3-HPAA could be a potential therapy for fertility decline of aging males in clinical practice. Video Abstract.

Aging induced testicular damage: analyzing the ameliorative potential of Mucuna pruriens seed extract

Mucuna pruriens Linn. (M. pruriens), a leguminous plant, was used extensively in Ayurveda, to treat male-related infertility. Previous studies have demonstrated antioxidant, androgenic, aphrodisiac, and spermatogenic properties of M. pruriens seed extract. Surprisingly, the biological activities of M. pruriens on aging-induced pathological changes in the testis microenvironment have never been explored and the present study was focused on the testing therapeutic efficacy of M. pruriens on aged rat testis. Male Wistar albino rats were grouped as; adult (3 months), aged (24 months), aged + M. pruriens and adult + M. pruriens (N = 6/group). The extract was administrated at a dose of 200 mg/kg body weight (dosage determined in our previous study) daily by gavage for 60 days. The total and free testosterone, FSH and LH levels were considerably increased in aged + M. pruriens. The diameter & volume of the seminiferous tubules, the height & volume of the epithelium, and the number of Leydig cells number were significantly decreased in aged rat testis, concomitantly connective tissue proportion was increased compared to adult rats. The seminiferous epithelium indicates significant rejuvenation or restoration of spermatogenic cells in aged + M. pruriens rat testis. The highlighting observations in aged + M. pruriens was increased in the following parameters i.e., tubular diameter (25%), number of tubules (35%), epithelial height (25%) & volume (20%), and number of Leydig cells (35%) when compared to untreated aged rat testis. The TNFα, NF-κB, cytochrome c, Caspase-9, Caspase-3, Bcl-2, Bax, PARP iNOS, and inflammatory and apoptotic factors were downregulated in aged + M. pruriens. M. pruriens was able to restore spermatogenesis and enhance the activity of Sertoli cells and Leydig cells and improve the pituitary-gonadal axis in aged rat testis and observations indicate the therapeutic activity of M. pruriens in aged rat testis.

Post-pubertal developmental trajectories of laryngeal shape and size in humans

Laryngeal morphotypes have been hypothesized related to both phonation and to laryngeal pathologies. Morphotypes have not been validated or demonstrated quantitatively and sources of shape and size variation are incompletely understood but are critical for the explanation of behavioral changes (e.g., changes of physical properties of a voice) and for therapeutic approaches to the larynx. This is the first study to take this crucial step and results are likely to have implications for surgeons and speech language pathologists. A stratified human sample was interrogated for phenotypic variation of the vocal organ. First, computed tomography image stacks were used to generate three-dimensional reconstructions of the thyroid cartilage. Then cartilage shapes were quantified using multivariate statistical analysis of high dimensional shape data from margins and surfaces of the thyroid cartilage. The effects of sex, age, body mass index (BMI) and body height on size and shape differences were analyzed. We found that sex, age, BMI and the age-sex interaction showed significant effects on the mixed sex sample. Among males, only age showed a strong effect. The thyroid cartilage increased in overall size, and the angulation between left and right lamina decreased in older males. Age, BMI and the age-height interaction were statistically significant factors within females. The angulation between left and right lamina increased in older females and was smaller in females with greater BMI. A cluster analysis confirmed the strong age effect on larynx shape in males and a complex interaction between the age, BMI and height variables in the female sample. The investigation demonstrated that age and BMI, two risk factors in a range of clinical conditions, are associated with shape and size variation of the human larynx. The effects influence shape differently in female and male larynges. The male-female shape dichotomy is partly size-dependent but predominantly size-independent.

Jiawei Runjing Decoction Improves Spermatogenesis of Cryptozoospermia With Varicocele by Regulating the Testicular Microenvironment: Two-Center Prospective Cohort Study

Objective: The aim of the study was to explore the evidence of JWRJD in the treatment of cryptozoospermia.

Methods: A total of 162 cryptozoospermia patients with varicocele who refused to undergo surgery were included from January 2021 to December 2021. They were divided into the Jiawei Runjing Decoction group (group A), tamoxifen group (group B), and no treatment group (group C), and after the follow-up for 3 months, therapeutic effectiveness was compared. Network pharmacology was used to analyze and validate the effects and mechanisms of JWRJD.

Results: Fifty-eight patients were treated with JWRJD, 55 with tamoxifen, and 49 without any treatment. After treatment, five patients were lost: one in group A, one in group B, and three in group C. The sperm count and the decrease of FSH in group A were significantly higher, but the degree of decline in the testicular volume and the degree of vein expansion have decreased significantly, which were closely related to the testicular volume (TV) [especially changes in the left testicular volume (ΔL-TV)], citric acid (CC) and its changes (ΔCC), and the vein width (VW) [especially left spermatic vein width (L-VW) and mean vein width (M-VW) and their changes (ΔL-VW and ΔM-VW)], as well as the sperm count before the treatment (bSC), which were the significant indexes to predict the therapeutic effect, especially for patients >35 years old and with grade III varicoceles. Network pharmacological analysis verifies that it can be regulated by fluid shear stress and the atherosclerosis pathway to improve the testicular microenvironment for spermatogenesis.

Conclusion: JWRJD may promote spermatogenesis in cryptozoospermia patients with varicocele, which may be closely related to improving the testicular microenvironment, especially for >35 year olds and grade III varicocele patients.

Therapeutic Effects of Bee Bread on Obesity-Induced Testicular-Derived Oxidative Stress, Inflammation, and Apoptosis in High-Fat Diet Obese Rat Model

Obesity is a debilitating disorder with a variety of problems including oxidative stress, inflammation, and apoptosis. The aim of our study was to investigate the therapeutic role of bee bread on oxidative stress, apoptosis, and inflammation in the testis of obese rats. Thirty-two adult male Sprague Dawley rats, with weights between 230–300 g, were distributed into four groups (n = 8/group), namely normal control (C), obese (Ob), obese + BB or obese + OR [high-fat diet (HFD) for 6 weeks then HFD plus bee bread or orlistat for another 6 weeks] groups. Bee bread (0.5 g/kg) or orlistat (10 mg/kg/day) was diluted with distilled water and administered daily for 6 weeks by oral gavage. There were significant decreases in the activities of antioxidant enzymes [glutathione-S-transferase (GST), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), glutathione reductase (GR)], glutathione (GSH)] and total antioxidant capacity (TAC) levels and mRNA expressions of nuclear factor erythroid 2–related factor 2 (Nrf2), superoxide dismutase (Sod), catalase (Cat) and glutathione peroxidase (Gpx) in the obese group relative to the control group. Meanwhile, the mRNA levels of pro-inflammatory markers, namely: inducible nitric oxide synthase (Inos), nuclear factor kappa B (Nf-κβ), tumour necrotic factor α (Tnf-α) and interleukin 1β (Il-1β) were significantly increased while interleukin (Il-10) was decreased in the obese group relative to the control group. Further, proliferating cell nuclear antigen (PCNA) immunoexpressions decreased while cleaved caspase-3 immunohistochemical staining increased significantly in the obese group, in addition to increases in the mRNA levels of p53, Bax, Caspases-8, 9 and 3, relative to the control group. Treatment with bee bread showed increases in antioxidant enzymes and PCNA immunoexpression, as well as decreases in inflammation and apoptosis markers in the testes. This study has shown that bee bread has therapeutic effects against oxidative stress, inflammation, apoptosis in the testis of HFD-induced obese male rats, thereby suggesting its role as a natural supplement capable of treating obesity-induced male reproductive impairment.

Hallmarks of Testicular Aging: The Challenge of Anti-Inflammatory and Antioxidant Therapies Using Natural and/or Pharmacological Compounds to Improve the Physiopathological Status of the Aged Male Gonad

The evolutionary theory of aging supports a trade-off relationship between reproduction and aging. Aging of the male reproductive system primarily affects the testes, leading to a decrease in the levels of sexual hormones, alterations in sperm quality and production, and a decline in fertility that does not necessarily involve a complete cessation of spermatogenesis. Inflammation, oxidation, and apoptosis are events considered as predictors of pathogenesis and the development of age-related diseases that are frequently observed in aged testes. Although the molecular mechanisms are still poorly understood, accumulating evidence points toward pro-inflammatory molecules and reactive oxygen species as primary contributing factors for testicular aging. However, the real impact of aging-related testicular alterations on fertility, reproductive health, and life span is far from being fully revealed. This work discusses the current knowledge on the impact of aging in the testis, particularly of aging-related dysregulated inflammation and oxidative damage on the functioning of its different cell populations. More interestingly, this review covers the potential benefits of anti-aging interventions and therapies using either pharmacological compounds (such as non-selective non-steroidal anti-inflammatory medication) or more natural alternatives (such as various nutraceuticals or even probiotics) that exhibit anti-inflammatory, antioxidant, and anti-apoptotic properties. Some of these are currently being investigated or are already in clinical use to delay or prevent testicular aging.