Seminal microflora in asymptomatic inflammatory (NIH IV category) prostatitis

Immune regulatory cytokines in seminal plasma of healthy men: A scoping review and analysis of variance

OBJECTIVE

Seminal plasma cytokines are associated with fertility and reproductive health, but progressing their clinical utility is hampered by absence of reference data on concentration ranges of relevant cytokines in healthy men. We employed a systematic approach to assemble current evidence on the concentrations of immune regulatory cytokines present in seminal plasma (SP) of normozoospermic and/or fertile men and evaluated the impact of different platform methodologies for cytokine quantification.

EVIDENCE REVIEW

A systematic literature search was performed utilising PubMed, Web of Science and Scopus. Databases were searched from inception until 30th June 2022 inclusive, using combinations of keywords pertaining to seminal fluid and cytokines, and was restricted to human participants. Original data with values reported as concentration of specific cytokines in SP of men clearly defined as fertile or normozoospermic were extracted from studies written in English.

RESULTS

A total of 3769 publications were initially identified, of which 118 fulfilled the eligibility criteria for inclusion. A total of 51 individual cytokines are detectable in SP of healthy men. The number of studies reporting on each cytokine range from 1 to >20. The reported concentrations for many cytokines linked with fertility status, including IL6, CXCL8/IL8, and TNFA, are highly variable between published studies. This is associated with the different immunoassay methodologies utilised and may be exacerbated by a lack of validation of assays to ensure suitability for SP assessment. Due to the large variation between studies, accurate reference ranges for healthy men cannot be determined from the published data.

CONCLUSIONS

The concentrations of cytokines and chemokines detected in SP is inconsistent and highly variable between studies and cohorts, limiting current capacity to define reference ranges for cytokine concentrations in fertile men. The lack of standardisation in methods used to process and store SP, and variation in platforms used to evaluate cytokine abundance, are factors contributing to the observed heterogeneity. To progress the clinical utility of SP cytokine analysis will require standardisation and validation of methodologies so that reference ranges for healthy fertile men can be defined.

Serum interleukin 6 and acute urinary retention in elderly men with benign prostatic hyperplasia in China: a cross-sectional study

Background

While acute urinary retention (AUR) is a severe complication of benign prostatic hyperplasia (BPH), it can also indicate the progression of this common disease in aging men. This study aimed at exploring the possible relationship between serum interleukin 6 (sIL-6) and AUR in BPH patients.

Methods

A cross-sectional study was conducted based on 256 elderly men with BPH in China. The association between the sIL-6 level and the occurrence of AUR was evaluated by univariate and multivariable logistic regressions. The receiver operating characteristic (ROC) curve was utilized to determine the discriminant validity of the sIL-6 level and the optimal cut-off value.

Results

The concentration of sIL-6 was significantly elevated in the AUR group (P<0.001). A positive correlation was observed between the sIL-6 level and AUR in BPH patients [odds ratio (OR) =1.365, 95% confidence interval (CI): 1.174-1.586, P<0.001]. Based on the ROC curve analysis for sIL-6, the optimal cut-off point of 4.475 pg/mL was set to identify the occurrence of AUR in these patients [area under the curve (AUC) =0.7596, 95% CI: 0.6976-0.8216, P<0.001]. A high sIL-6 level (≥4.475 pg/mL) had a significantly stronger correlation with AUR (OR =9.666, 95% CI: 4.347-21.491, P<0.001).

Conclusions

There was a positive correlation between the sIL-6 level and the occurrence of AUR in elderly Chinese patients with BPH. This study provides potential strategies for the screening of BPH individuals with a possible risk of AUR, which may contribute to the early implementation of effective interventions to improve the quality of life and prognosis. Long-term prospective studies are still required to further illustrate the causal relationship.

The seminal microbiome in health and disease

Owing to the fact that there are more microbial than human cells in our body and that humans contain more microbial than human genes, the microbiome has huge potential to influence human physiology, both in health and in disease. The use of next-generation sequencing technologies has helped to elucidate functional, quantitative and mechanistic aspects of the complex microorganism-host interactions that underlie human physiology and pathophysiology. The microbiome of semen is a field of increasing scientific interest, although this microbial niche is currently understudied compared with other areas of microbiome research. However, emerging evidence is beginning to indicate that the seminal microbiome has important implications for the reproductive health of men, the health of the couple and even the health of offspring, owing to transfer of microorganisms to the partner and offspring. As this field expands, further carefully designed and well-powered studies are required to unravel the true nature and role of the seminal microbiome.

Impact of sexual debut on culturable human seminal microbiota

Micro-organisms are tightly integrated into host-microbiota ecosystem. Microbiota of human semen has been studied so far mostly in case of infertility or prostatitis. We aimed to reveal possible impact of sexual debut on seminal microbiota in healthy young men. The study group included 68 young healthy men, of them 12 men without sexual experience, 11 men with single lifetime sexual partner and 45 men with multiple lifetime sexual partners. Basic semen parameters were similar for all subgroups, and no correlation between sexual experience and WBC counts in semen was found. A man could harbour one to nine different bacteria in his semen; the total concentration of bacteria ranged from 2.3 to 7.3 log₁₀ CFU/mL of semen. Lower total bacterial concentration and lower bacterial diversity was observed in men without sexual experience than in sexually experienced men (p < 0.05), with significant positive correlation between these two parameters (r = 0.54; p < 0.0001). In conclusion, the sexual debut is associated with the enrichment of seminal microbiota but not with the influx of WBC or changes in basic seminal parameters.

Inflammatory reaction found in prostate-specific material - method standardization and proposed optimal cut-off points

Prostatitis classification as well as treatment decisions are primarily based on differentiation of the inflammatory status in prostate-specific material. At the same time, methods used for detection of inflammation are semi-quantitative and not finally standardized. The main aim of this study was to suggest more precise methods for detection of prostate inflammatory status. Additional aims were to define optimal cut-off points of various tests in order to discriminate between inflammatory and non-inflammatory condition and to analyze the prevalence of inflammatory prostatitis in the groups of symptomatic prostatitis, lower urinary tract symptoms and control subjects. This prospective study included 541 patients (with prostatitis symptoms, with lower urinary tract symptoms and controls) at Tartu University Hospital, Estonia. Leukocyte counts in first-void urine, expressed prostatic secretion and post-massage urine as well as interleukin-6 in prostate secretion specimens were determined. Based on ROC curve analysis, we detected potential normal values for leukocytes in expressed prostatic secretion (<0.5 m/mL), leukocytes in post-massage urine (<4 WBCs per HPF) and IL-6 in prostatic secretion (<50 nmol/mL). Using these newly defined normal values, we detected inflammatory reaction in prostate-specific materials in 24.3%, 53.4% and 69% in control, lower urinary tract symptoms and prostatitis group, respectively.

LIMITATION

only subjects with prostatic fluid volume >0.04 mL were included. We propose standardized method for analysis of inflammatory reaction in prostate-specific materials. Based on these newly defined normal values, we verified high prevalence of inflammatory forms of disease in both study groups, but also high prevalence of asymptomatic inflammatory prostatitis among control group of Estonian men. Combining results of analysis of the different inflammatory markers from available prostate-specific materials allows us to differentiate better between inflammatory and non-inflammatory forms of prostate diseases and hence to choose more precise treatment strategies.

Seminal microbiome in men with and without prostatitis

OBJECTIVES

To profile the seminal microbiome applying next generation sequencing.

METHODS

Semen samples of 67 men were involved in the study (21 men with and 46 men without prostatitis). Seminal microbiomes were profiled applying the method that uses combinatorial sequence tags attached to polymerase chain reaction primers that amplify the ribosomal ribonucleic acid V6 region. Amplified polymerase chain reaction products were sequenced using an Illumina paired-end protocol on HiSeq2000 platform.

RESULTS

The most abundant phylum in semen was Firmicutes, comprising nearly half of the sequences found (median 41.7%, quartiles 28.5-47.2%) followed by Bacteroidetes, Proteobacteria and Actinobacteria. The counts of lactobacilli were higher in healthy men than prostatitis patients (27% [20.2-34.6%] vs 20.2% [4.9-25.0%]; P = 0.05), especially for Lactobacillus iners. Proteobacteria comprised higher proportions in prostatitis patients than healthy men. The species richness was higher in prostatitis patients than healthy men (inverted Simpson index 13.5 ± 5.8 vs 10.3 ± 4.0).

CONCLUSIONS

The semen of chronic prostatitis patients contains fewer health-supporting lactobacilli, and has higher species diversity than that of healthy men. Firmicutes (especially lactobacilli), Bacteroidetes, Proteobacteria and Actinobacteria comprise the highest proportion of seminal microbiome.

Coryneform bacteria in human semen: inter-assay variability in species composition detection and biofilm production ability

Background

Coryneform bacteria constitute an important segment of male urogenital microbiota. They have been generally considered as saprophytes, although some species have been associated with prostatitis as well. At the same time, biofilm infections have been suspected as a cause of prostatitis.

Objective

To identify a set of coryneform bacteria isolated from semen of either healthy men or prostatitis patients applying different methods to reveal inter-assay variability and to determine their ability of adhesion and biofilm production.

Design

Coryneform bacteria were identified by API Coryne 2.0 biochemical identification system and 16S rDNA sequencing using different primer sets. Quantitative assessment of biofilm production was performed using crystal violet binding assay method.

Results

The most common species were Corynebacterium seminale, C. minutissimum, and Dermabacter hominis. Altogether 14 species and related genera were found. We observed the best inter-assay agreement when identifying C. seminale. Biofilm was observed in 7 out of 24 strains. The biofilm-producing strains belonged to Arthrobacter cumminsii, Dermabacter hominis, C. minutissimum, and Actinomyces neuii. No differences were found between the strains originating from prostatitis patients and healthy men. Dermabacter hominis strains were more potent biofilm producers than C. seminale strains (p=0.048).

Conclusions

We can conclude that a wide variety of coryneform bacteria can be found from the male genital tract, although their exact identification is problematic due to insufficient representation in databases. Nearly one third of the strains are able to form biofilm that may give them an advantage for surviving several host- and treatment-related conditions.

Characterisation of the bacterial community in expressed prostatic secretions from patients with chronic prostatitis/chronic pelvic pain syndrome and infertile men: a preliminary investigation

The expressed prostatic secretions (EPSs) of men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), infertile men and normal men were subjected to microbiological study. EPSs were collected from the subjects, which included 26 normal men, 11 infertile patients and 51 CP/CPPS patients. DNA was extracted from each specimen, and the V3 regions of the 16S rRNA genes were amplified using universal bacterial primers. The results showed that the EPS 16S rRNA gene-positive rate in the CP/CPPS and infertile patients was much higher than in the normal men, but without any difference among the three patient groups. The denaturing gradient gel electrophoresis (DGGE) method was used to characterize the EPS bacterial community structure of the prostate fluid from patients with CP/CPPS or infertility issues. Principal component analysis (PCA) and partial least squares (PLS) analyses of PCR-DGGE profiles revealed that the EPS bacterial community structure differed among the three groups. Three bands were identified as the key factors responsible for the discrepancy between CP/CPPS patients and infertile patients (P<0.05). Two bands were identified as priority factors in the discrepancy of category IIIA and category IIIB prostatitis patients (P<0.05). According to this research, the ecological balance of the prostate and low urethra tract, when considered as a microenvironment, might play an important role in the maintenance of a healthy male reproductive tract.

Influence of sexual intercourse on genital tract microbiota in infertile couples

Several studies have suggested the association of disturbed genital tract microbiota with infertility. Our aim was to clarify the influence of sexual intercourse on partner's genital tract microbiota in infertile couples. Seventeen couples were studied, and in 5 men inflammatory prostatitis (IP) was diagnosed. Semen samples were collected during menstruation of the female counterpart, two self-collected vaginal samples were taken 3-5 days later - before intercourse and 8-12 h after intercourse. Ureaplasma parvum was found in 59% of women, its prevalence was higher in women whose partner had IP, as well as in half of their male partners. Sexual intercourse caused significant shifts in vaginal microbiota - increase of Nugent score and shifts in cultured microbiota (emergence and disappearance of several species). These changes were less expressed in the presence of normal vaginal microbiota but more prominent in the partners of IP men. These changes may interfere with fertilization.

Prevalence of asymptomatic inflammatory (National Institutes of Health Category IV) prostatitis in young men according to semen analysis

OBJECTIVES

To determine the prevalence of asymptomatic inflammatory (National Institutes of Health category IV) prostatitis in a cross-sectional community sample of young men.

METHODS

The study group consisted of 565 men aged 18.9 +/- 1.8 years (mean +/- standard deviation). Cytologic examination of all ejaculates (using Bryan-Leishman stained slides), as well as analysis for basic semen parameters (volume, concentration, and motility) and clinical examination for possible pathologies in the genital region, were performed. Subjects with any clinical symptoms of inflammation were excluded. Levels of prostate-specific antigen in blood serum and interleukin-6 in seminal plasma were determined as well.

RESULTS

The prevalence of asymptomatic inflammatory prostatitis (greater than 1 x 10(6) white blood cells [WBC]/mL in semen, according to World Health Organization guidelines) was 6.0%, but when we used a lower threshold suggested by our previous studies (greater than 0.2 x 10(6) WBC/mL), the prevalence was 19.0%. In this study the analysis did not show any significant effect of leukocytospermia on sperm quality, except higher sperm concentration in subjects with moderate leukocytospermia (0.2-1 x 10(6) WBC/mL). We did not detect any seasonal differences in the prevalence of asymptomatic inflammatory prostatitis. Interleukin-6 and prostate-specific antigen levels were significantly higher in leukocytospermic subjects than in those without leukocytospermia.

CONCLUSIONS

Asymptomatic inflammatory prostatitis has a notable prevalence among healthy young men, suggesting the need for further studies to investigate pathogenetic mechanisms of the disease. Lack of negative effect of leukocytospermia on basic semen parameters may indicate higher functional reserve of accessory sex glands in this age group.