Seminal macrophages in ejaculates from men with couple infertility

Efferocytosis and infertility: Implications for diagnosis and therapy

Recent research has shed light on the intricate connection between efferocytosis and infertility, revealing its dysregulation as a contributing factor in various reproductive diseases. Despite the multifaceted nature of infertility etiology, the impact of insufficient clearance of apoptotic cells on fertility has emerged as a focal point. Notably, the removal of apoptotic cells through phagocytosis in the female reproductive system has been a subject of extensive investigation in the field of infertility. Additionally, special functions performed by immune system cell types, such as macrophages and Sertoli cells, in the male reproductive system underscore their significance in spermatogenesis and the efferocytosis of apoptotic germ cells. Dysregulation of efferocytosis emerges as a critical factor contributing to reproductive challenges, such as low pregnancy rates, miscarriages, and implantation failures. Moreover, defective efferocytosis can lead to compromised implantation, recurrent miscarriages, and unsuccessful assisted reproductive procedures. This review article aims to provide a comprehensive overview of efferocytosis in the context of infertility. Molecular mechanisms underlying efferocytosis, its relevance in both female and male infertility, and its implications in various reproductive diseases are elucidated. The elucidation of the intricate relationship between efferocytosis and infertility not only facilitates diagnosis but also paves the way for targeted therapeutic interventions.

Alternative polarization of resident macrophages improves hyperglycemia-associated male infertility

Recent studies have demonstrated that hyperglycemia induces inflammation in male reproductive system to cause sperm damages and infertility, which may be associated with re-polarization of tissue macrophages from an anti-inflammation M2-like subtype to a pro-inflammation M1-like subtype. However, the underlying mechanisms are not fully determined and a practical approach to interfere with the progression of infertility is lacking. Here, we transduced the testicular macrophages back to the M2-like phenotype with adeno-associated viruses carrying an M2-trigger, Jumonji domain-containing protein D3 (JMJD3), under a macrophage-specific CD68 promoter (CD68p-JMJD3), in streptozotocin-induced diabetic mice. We found that JMJD3-induced M2-polarization of testicular macrophages significantly improved the mating capability of diabetic male mice. The diabetes-induced impairment of the motility of spermatozoa and the decreases in the serum and testicular testosterone levels were both significantly alleviated in CD68p-JMJD3-treated diabetic mice. Thus, our study proposes a practical strategy to treat hyperglycemia-associated infertility.

Effect of macrophages in semen on sperm quality

BACKGROUND

This was a cross-sectional study in China which analyzed the levels of macrophages (Mφ) in semen and evaluated the influence of Mφ levels in semen on sperm quality.

METHODS

The subjects involves 78 males, 25- to 35-year old. The samples were divided into a low group (Mφ < 6 × 105/ml) and a high group (Mφ > 6 × 105/ml). Evaluation included consideration of the influencing factors of male semen quality, macrophage concentration, sperm motility, morphology, membrane integrity DNA fragmentation index (DFI), anti-sperm antibodies (AsAb), IL-10, and IL-12 in semen.

RESULTS

There was no difference in the physical or chemical indices of the semen, sperm concentration, AsAb, IL-10, or IL-12 between the two groups (P > 0.05). The percentage of sperm forward motility (PR%), the rate of normal sperm shape, and the integrity of cell membranes in the low group were higher than those in the high group (P < 0.05), while the percentage of sperm inactivity (IM%), the rate of sperm head deformity, the rate of deformity in the neck and middle segment, the sperm deformity index (SDI), the teratozoospermia index (TZI), and the sperm DFI in the low group were lower than those in the high group (P < 0.05). The concentration of Mφ in the semen was linearly correlated with sperm concentration, sperm PR%, IM%, sperm normal shape rate, head deformity rate, neck and middle deformity rate, SDI, TZI, sperm DFI, and sperm cell membrane integrity (P < 0.05), but there was no linear correlation with IL-10 or IL-12 (P > 0.05).

CONCLUSIONS

The Mφ concentration in semen is not significantly correlated with semen volume or sperm concentration, but negatively correlated with sperm motility, morphology, cell membrane integrity, and DNA damage rate. There is no significant correlation between the macrophages and the concentration of IL-10 or IL-12.

Standard Semen Parameters vs. Sperm Kinematics to Predict Sperm DNA Damage

Purpose

The aims of this study were to associate sperm kinematics and standard semen parameters with sperm DNA damage and to evaluate whether the addition of sperm kinematics improve the multivariable prediction of sperm DNA fragmentation compared to standard semen parameters alone.

Materials and Methods

We evaluated sperm kinematics, standard semen parameters, and DNA fragmentation index (DFI) in 122 men. Univariate and multivariate logistic regression models were fitted to evaluate the association of sperm kinematics and standard semen parameters with pathologically damaged sperm DNA (DFI≥26%), and receiver operating characteristics (ROC) curves were calculated for these models.

Results

On univariate analyses, average velocity, curvilinear velocity, straight-line velocity, straightness (STR), beat-cross frequency (BCF), and the percentage of progressive motile sperm cells (PPMS) were significantly associated with pathologically damaged sperm DNA. Likewise, among standard semen parameters, sperm concentration, progressive motility, normal morphology, and vitality were found to be linked with sperm DNA damage. On the multivariate analysis, vitality was the strongest predictor of pathologically damaged sperm DNA with an area under the ROC curve (AUROC) of 88.3%. Adding STR, BCF, and PPMS to vitality increased the AUROC to the significant extent of 91.5%.

Conclusions

Sperm vitality is the most accurate routine-based laboratory test for the prediction of pathologically damaged sperm DNA, but the addition of sperm kinematics increases its accuracy. Both standard semen parameters and sperm kinematics are complementary in predicting pathologically damaged sperm DNA, and might serve as a new tool to screen for fertile men.

Monocyte-derived extracellular trap (MET) formation induces aggregation and affects motility of human spermatozoa in vitro

The presence of bacteria and/or leukocytes can alter semen quality resulting in low sperm quality and infertility. Inflammation or infection increases the numbers of PMN or macrophages/monocytes in male genital tract. Release of extracellular traps (ETs) by leukocytes has been recognized as a novel mechanism of early host innate immunity, in response to invasive pathogens. This is the first work that evaluated the mechanism of triggered ETs in monocytes co-incubated with spermatozoa or bacteria and the effect on sperm function. Selected spermatozoa and human monocytes isolated from peripheral blood were obtained by healthy donors. Two experimental models were developed, one aseptic (non-infectious) incubating spermatozoa and monocytes, and septic models (infectious) incubating spermatozoa with monocytes and uropathogenic Escherichia coli (E. coli). ETs of monocytes (METs) (DNA, global histone and citrullinated histones) were visualized by scanning electron microscopy (SEM) and immunofluorescence analyses. Progressive motility was performed at 0, 10, 30, 60, and 180 min after co-incubation with CASA system. SEM- and immunofluorescence-analyses revealed human spermatozoa alone or in the presence of E. coli as strong inducers METs. In aseptic model, the motility decreased to 65.2 ± 3.5% at 10 min of incubation and 29.3 ± 3.3% at 30 min (p < 0.001). In septic model, motility decreased to 44.5 ± 5.9% (10 min) and 12.7 ± 2.2% (30 min) (p < 0.001). MET-derived small spermatozoa aggregations were observed in both models. METs might physically block spermatozoa and decrease motility after a brief contact. This may impair male fertility, especially in patients with genital tract infections or chronic inflammation. Abbreviations: PMN: polymorphonuclear; ETs: extracellular traps; E. coli: Escherichia coli; METs: ETs of monocytes; SEM: scanning electron microscopy; NE: neutrophil elastase; MPO: myeloperoxidase; MAGI: male accessory gland infection; PBMC: peripheral blood mononuclear cells; RT: room temperature; CFU: colony forming units; CASA: computer-aided sperm analysis; H4Cit3: histone H4 citrullinated 3.

Urogenital Infection as a Risk Factor for Male Infertility

BACKGROUND

Infections of the genital tract are considered common causes of male fertility disorders, with a prevalence of 6-10%. Most of the affected men are asymptomatic. The diagnostic evaluation is based mainly on laboratory testing. Inconsistent diagnostic criteria have been applied to date, and this may explain the controversial debate about the role of infection and inflammation in the genital tract as a cause of infertility. The risk of an irreversible fertility disorder should not be underestimated.

METHODS

This review is based on pertinent publications retrieved by a selective literature search in PubMed, including guidelines from Germany and abroad and systematic review articles.

RESULTS

The main causes of inflammatory disease of the male genital tract are ascending sexually transmitted infections (STIs) and uropathogens. Chronic prostatitis has no more than a limited influence on ejaculate variables. By contrast, approximately 10% of men who have had acute epididymitis develop persistent azoospermia thereafter, and 30% have oligozoospermia. Obstruction of the excurrent ducts can ensue, as can post-infectious disturbances of spermatogenesis. The differential diagnostic evaluation includes the determination of testicular volumes, hormone concentrations, and ejaculate variables. Epidemiological data are lacking with regard to infertility after primary orchitis of infectious origin; however, up to 25% of testicular biopsies obtained from infertile men reveal focal inflammatory reactions. Multiple studies have suggested a deleterious effect of leukocytes and inflammatory mediators on sperm para - meters. On the other hand, the clinical significance of bacteriospermia remains unclear.

CONCLUSION

Any suspicion of an infectious or inflammatory disease in the male genital tract should prompt a systematic diagnostic evaluation and appropriate treatment. For patients with obstructive azoospermia, the etiology and site of the obstruction determine the surgical approach to be taken. In the near future, the elucidation of underlying pathophysiological mechanisms and the identification of suitable biomarkers may enable new strategies for conservative treatment.

Detection of macrophages in rabbit semen and their relationship with semen quality

We aimed at the evaluating the occurrence of macrophages in rabbit semen and finding possible relationship between macrophage concentration and spermatozoa quality. The concentration of macrophages in semen samples from broiler rabbit males of lines M91 and P91 (n = 30) without overt evidence of genital tract infections was determined using monocyte/macrophage lineage antigen CD14 and flow cytometry. Then the rabbits were assigned into three groups according to the macrophage concentration in semen (MΦ1 group with less than 1 × 10⁶ macrophages/mL, MΦ2 group with 1.5-3.5 × 10⁶ macrophages/mL and MΦ3 group with more than 8 × 10⁶ macrophages/mL). Spermatozoa viability parameters such as occurrence of apoptotic (Yo-Pro-1) and dead/necrotic (propidium iodide) spermatozoa and plasma membrane integrity (PNA-Fluos) were evaluated using flow cytometry. Sperm motility parameters were determined by CASA (Computer Assisted Semen Analysis). Ultrastructural detection of macrophages was performed using transmission electron microscopy. Spermatozoa fertility potential was examined after intravaginal artificial insemination of rabbit doses. Significantly higher proportions of the apoptotic and necrotic spermatozoa and spermatozoa with lower plasma membrane integrity were revealed in the MΦ3 group compared to MΦ1 and MΦ2 groups. The percentage value of total motility and progressive movement was significantly highest in the MΦ1 group, whilst lowest in the MΦ3 group. The conception rate and the kindling rate were significantly decreased in the group with the highest macrophage concentration (MΦ3). Based on our results we can conclude that the abundance of seminal macrophages in the rabbit semen may be closely associated with poor spermatozoa quality.

Spermiophages on testicular fine needle aspiration cytology: A rare finding

Macrophages usually reside in the testicular interstitial tissues and are normally not found within the seminiferous tubules. However, in certain cases of male infertility, the macrophages are activated and can then be found within the tubules where they can ingest spermatozoa and are labeled as "spermiophages." FNAC was performed in a 36 year male with history of primary infertility. On microscopy, smears made from right testis were indicative of hypospermatogenesis. On the contrary, smears made from the left testis were very cellular showing Sertoli cells and the entire spectrum of normal spermatogenesis. Also seen were many isolated spermiophages. The cytological impression given for the left testis was normal spermatogenesis with numerous spermiophages. Thus the patient fell in the category of obstructive azoospermia (OA). According to currently adopted hypothesis, macrophages carry ingested sperm heads with some antigenic components to the basal capillaries which may result in the formation of autoantibodies against the spermatozoa. This situation may further diminish the chances of fertility in men. The origin of these spermiophage cells is unknown. Although commonly reported in semen and epididymal biopsies, they have not been reported to occur on testicular fine needle aspiration cytology (FNAC). In our case, no sperms were found on semen examination which were easily picked up on testicular FNAC indicating usefulness of the latter in the diagnosis of cases of male infertility and eliminating the need for a testicular biopsy.

Influence of Macrophages on the Rooster Spermatozoa Quality

The goal of this study was to evaluate the occurrence of macrophages in rooster semen and to investigate their impact on the spermatozoa quality. Ross 308 breeder males (n = 30) with no evidence of genital tract infections were used to determine the concentration of macrophages using fluorescently conjugated acetylated low-density lipoprotein (AcLDL). Subsequently, the roosters were divided into two groups on the basis of semen macrophage concentration, and semen quality was compared in two heterospermic samples. We applied computer-assisted semen analysis (CASA) system to determine motility parameters. Fluorescence microscopy and flow cytometry were used to evaluate occurrence of apoptotic and dead spermatozoa. Spermatozoa fertility potential was examined after intravaginal artificial insemination of hens. Eighteen roosters (control group) contained 0.2-3% of macrophages within spermatozoa population and ten roosters (macrophage group) had 10-15% of macrophages. Males from macrophage group had lower (p < 0.05) motility parameters (total and progressive movement, velocity curved line) and increased concentration of dead spermatozoa detected by flow cytometry and fluorescence microscopy (p < 0.001 and p ˂ 0.05, respectively). Differences (p < 0.05) between fluorescent microscopy and flow cytometry in results on spermatozoa apoptosis and viability were observed. No significant difference was found between groups in fertility of spermatozoa. In conclusion, the higher presence of macrophages in rooster semen may have a negative effect on some parameters of rooster spermatozoa evaluated in vitro. Furthermore, our study suggests that flow cytometry allows more precise examination of spermatozoa viability and apoptosis in a very short time compared with the fluorescent microscopy.

Male infertility workup needs additional testing of expressed prostatic secretion and/or post-massage urine

The male factor accounts for almost 50% of infertility cases. Inflammation may reduce semen quality via several pathways, including oxidative stress (OxS). As male infertility routinely is assessed using semen analysis only, the possible presence of non-leukocytospermic asymptomatic inflammatory prostatitis may be overlooked. We compared local and systemic OxS levels in male partners of infertile couples with different inflammation patterns in their genital tract and/or oligospermia. Subjects (n=143) were grouped according to inflammation in their semen, expressed prostatic secretion (EPS), and/or post-massage urine (post-M). Systemic (8-isoprostanes in urine) and local (diene conjugates and total antioxidant capacity in seminal plasma) OxS was measured The levels of OxS markers were significantly elevated in both severe inflammation groups--leukocytospermic men and subjects whose inflammation was limited only to EPS and/or post-M. Comparison between oligospermic and non-oligospermic men with genital tract inflammation, and oligozoospermic men with or without inflammation in the genital tract indicated that inflammation but not oligospermia status had significant impact on the measured OxS markers. Hence, a high leukocyte count in prostate-specific materials (EPS, post-M), even in absence of clear leukocytopsermia, is an important source of local and systemic OxS that may be associated with male infertility and affect general health. We suggest including the tests for detection of inflammation of the prostate into the workup of infertile men as was suggested in the WHO 1993 recommendation.